US can spend working force, crew, aluminium, steel, engines, fuel and whatnot to make strategic bombing far better than other belligerents.
There can be no denying air power in general is a vital force multiplier, particularly against a foe that has invested in it heavily themselves.
There is a heck of a lot more question about the value of
strategic air power. Again, to deny it has any worth whatsoever is to take a ridiculously extreme position--but to pretend it can be a war-winning arm of the military, which was the thesis of interwar advocates of "Victory through air power," is to take an opposite and ridiculous extreme.
One simply cannot surrender to bombs, but all the major gurus of interwar advocacy suggested that victory would be achieved by a mechanism that simply never works, and can't come close to working.
Now there is no question that bombing does disrupt enemy capabilities, to a measurable degree, and that attempting defense against this threat does tie down more of what the enemy has left.
In fact for instance by most metrics, the Great War attempt at terror bombing via Zeppelins (and technically, some Schütte-Lanz models of rigid airship as well) waged against Britain was a pathetic failure, with bombing attacks going astray by entire regions, often bombing open countryside in the impression that some city or other was being bombed, in pathetic tonnages versus WWII. But one thing it did achieve--a substantial diversion of mobilization of force from the active fronts to air defense over Britain, and that was a measurable accomplishment of the attempt.
Whether the magnitude of the diversion of Allied resources compared to the cost of the Central Power effort is another question of course.
We are left then with objective, material impediments bombing accomplishes, and the imposition of an air defense cost, as real factors to consider.
These are the only gains we can reasonably claim are useful combat effects, to set against the cost of sustaining such attacks, in estimating cost-effectiveness.
Whereas the decision was made, before the war, both in Britain and the USA, to bet heavily on strategic bombing as a war winner, before the realistic data on how well it actually worked was in, and with a huge emphasis on platitudes that proved quite far from reality:
1) that people would in fact in effect surrender to bombing by demoralization;
2) that "the bomber will get through," which first led to decisions nerfing the effectiveness of interceptors lest the thesis on which a service claimed the status of independent command be undermined, followed by massive losses as it was shown that the bomber quite often would not get through, leading to massive investments to cover the sunk cost of a big bet on terror bombing such as belatedly providing escort fighter cover and attempting to armor and heavily arm the bombers themselves;
3) that "precision bombing" could accomplish such objectives as sinking warships, or as the failure of the terror bombing/general derangement bombing sank in, that vital works and resources and installations like rail junctures, POL distribution and stocks, etc could be efficiently targeted.
1 is pretty much false. 2 and 3 have some merit, but again, to be realistic in cost/benefit estimates we have to be realistic about the complete costs and about the limits of effectiveness. Not only were defended targets not nearly as easy to hit as bombing advocates asserted, the derangement caused by successfully hitting them with bombs it was feasible to deliver was generally a lot less than assumed. Again and again, facilities that took serious bomb damage were up and running again quite quickly.
The costs involved are huge, and go far beyond just making the airframes or even the opportunity cost of committing men to be pilots, aircrew and mechanics. To achieve the sort of performance desired, it was necessary to make aircraft that made heavy demands in terms of concrete reinforced runways; the cost of the concrete construction alone was a really significant cost factor in WWII.
Indeed the USA had resources to burn versus other powers; some could afford more men, but none could afford more extravagant use of material resources.
The point here being, the commitment to Victory Through Air Power was such an extravagant use.
Now air power has many aspects to be sure. Good fighter-interceptors of one phase of the war could generally be repurposed as tactical attack planes when they were no longer suitable as air superiority fighters, or for other vital auxiliary uses, such as reconnaissance (big bombers also could excel in that secondary role, particularly during the Cold War, or over stretches of ocean). The most vital force multiplier of air power is that of supporting land and sea surface defenses and attacks; if one can do this under cover of air superiority over the battlefield for one's own side, the "multiplication" of one's own side's effectiveness, and inversely the decimation of the other side's effectiveness, are both large factors. In the event the two air forces are hotly engaged with fluctuating success, the outcome is similarly fluctuating on the surface (and ASW) fields. What is certain is that if either side concedes air superiority to the other, they fight at a severe disadvantage.
To the extent that deep penetrating air strikes have effect, this is also true of strategic bombing, but if there is no presence of the enemy on the ground, even being wide open to air strikes one cannot effectively fend off is a lot less devastating than if that enemy could press the opportunities such bombing would open up and seize ground, follow through on neutralizing assets, and take the surrender of forces and regions.
Strategic bombers, if one can escort the bombers (or can make them otherwise less vulnerable, like flying in night), are a great thing for opening the second front in a most expedient manner.
Even with quite effective long range fighter escort, Allied (read, US and British, mostly, the Soviets did not consistently pursue long range strategic bombing) attrition rates on bomber strikes remained quite high. I am very skeptical it was generally the most cost effective use of Western Allied overall airpower potential.
As a "second front" it is close to useless. Consider for instance the effect of quite a deep British penetration into German airspace to wreck Von Braun's V2 development operations at Peenemünde; the upshot was to relocate the works into death-camp worked new sites, armored and buried in mine shafts, in the general region of "Camp Dora," itself a broad complex of slave camps. (Von Braun's workers included quite skilled draftsmen, employed as such--who were not even fed). Now one can high-five oneself that this cost the regime serious diversions of resources, since extra effort had to go into digging up the suitably sheltered sites, equipping them, and no doubt if Peenemünde had been left alone, and its approaches, it would have been somewhat cheaper for them to distribute the rockets as well. But the question is, is this really tantamount to opening a "second front?" Clearly not--nor is it cost-effective if one factors in RAF losses and the high cost of setting up the capabilities of Bomber Command in the first place. Calling this a "second front" is just wartime propaganda, not a serious substitute for one.
Germany can opt to ignore bombers and hope they don't hit something, or can opt to defend against them. The last option was pursued, and Allied escort fighters can make a short work of the LW defenders provide there is meaningful escort force in the 1st place, already by early 1943 this time around.
But the Germans were able to impose such costs on the Allies too, without investing in bombers of the B-17, -24, 29 types or the heavy types the RAF invested in (which were capable of bigger bomb loads but had to fly at lower altitudes, and therefore remained night bombers). The types they did focus on were more suited to front line attack purposes, and their most egregious (but not massively invested in) errors related to trying to make big bombers function like the smaller attack plane types.
The Allies won because they were huger, ultimately. The USSR had massive strategic depth and manpower, and crucial war production industries were located far behind the borders, and of course access to US and British aid; Britain had (somewhat vulnerable) access to world resources and the USA between domestic productivity and plenty of credit to cover the cost of obtaining materials not so suitable to US domestic production, cemented this.
Obviously we have to use judgement to decide which aspects of Allied peculiarities of approach were force multipliers and which were unfortunate wastes. Most of this thread is devoted to gun porn and unreasonable foresight, whereas I think that there was a certain advantage to be had, for powers that had staying power, in being reluctant and late to the fight, in avoiding by and large sinking too much production potential in stuff and in training that would not be appropriate for the actual fight. One pays a price for this, of course, but I think it is a mistake to chide people for not planning with perfect foresight for the war that would evolve with desperate move and countermove, when the nations we are chiding first of all sought to avoid war at all, and only when the options of peace were foreclosed turned reluctantly to winning it. This reluctance definitely cost the Allies in the form of poor preparation, but aside from the technical advantages coming from late wartime developed models of this or that that were suited to actual combat needs, there was I think a serious moral advantage as well; the various mobilized peoples of the Allies knew why they were fighting and that they should persevere through difficulties to victory.
I think the story of UK-USA devotion to "victory through airpower" is a cautionary tale about how much worse it could have been if the Anglosphere had been pugnacious and gung ho to fight through the '30s; the specific devotion to a form of airpower that relied on false premises and was particularly inefficient has been covered by the general achievement of victory and transformed into a pernicious myth; it bit the USA in the ass a second time in the later '40s when the inflated notions of victory through nuclear air power undermined maintenance of more balanced forces, which left us pretty much flat footed in the early phase of the Korean War (and once again, a silver lining to the dark cloud of poor preparation took the form of lots of reserve potential to devise new front line combat designs, in aircraft in particular, to meet unforeseen and complacently neglected enemy capabilities in the matter of air combat).
The fact of global nuclear balance of terror is a fact we cannot leave out of reckoning, but the paradox of the inefficiency of this monstrously efficient mode of dealing mass destruction on a foe only highlights the basic fallacy of pretending to be able to achieve victory by mass destruction of the foe all by itself. The machinery of Cold War intercontinental nuclear strike capability, massive and expensive though it is, was in the later Cold War dwarfed by the cost and scale of mobilization of much less wholesale means of destruction...and again, even with the balance of terror holding us from using any nuclear capability anywhere, the fallacy of victory through devastating strikes from the air was demonstrated again in Vietnam, and again in Iraq. Only following through with balanced forces to actually invade and conquer territory can anything approximating victory be achieved, and then too it is a matter of having a sane aim to achieve.
