Never said you'd arm everyone with them. You don't need that many to make melee combat an insanely bad idea. It isn't like flamethrowers require that much complexity to make either (and without cars the fuel is plentiful enough). Heck, they could have appeared in the first book, but barring that by the time you get 8+ years out they should definitely have a presence.
By the 2nd book people aren't barely surviving at all. They also have multiple engineers available, so it isn't like they don't have experts that could design more advanced weapons. I mean, heck, it's well-known there are magazine-based crossbows historically and with our advanced engineering today we could do even better. But, of course, like chemistry, this isn't explored to any meaningful degree despite the ready presence of engineers.
And Havel was in the military too. There are plenty of ex-military people that survive. There's really no justification in reality for long bows being presented as so awesome. Crossbows supplanted them for many good reasons. Beyond that, it most certainly DOES matter what weapon you are using -- what kind of silly statement is that?
Which are stated to be inferior to the longbow in range and killing power, which is ridiculous. The fact Stirling didn't even keep things accurate with the historical items he was using just makes the books even worse.
I am going to assume you have no experience with hand to hand combat. Why don't you read up on the training the given to police officers on dealing with opponents armed with knives? A person with a edged weapon can close a rather large distance in such a short amount of time even a well trained officer cannot draw his pistol. Your dream weapons are not going to end melee combat.
Oh it's common knowledge huh? Can you build a flamethrower with hand tools out of the scraps in your house? What range are you going to have? How many bursts will it have? What will be the duration of those bursts? How much fuel can you carry? If you're carrying fuel who is carrying the water/food/shelter for you? I can walk down into my den and take my Scutum, gladius, pilum, and hasta off the wall and be ready. How about you?
It not a silly statement. The fact you don't understand it tells me a lot about your ability to lead. Would you like historical examples? In the Franco-Prussian war the French rifle out ranged the German rifle 2 to 1: German's won due to better leadership. In the battle of France the French fielded better tanks than the Germans: German's won due to better leadership and tactics. Hedge row country Normandy: German Panther tanks much better than the British and Americans tanks: Victory Allies due to better logistics and air support. US convoy in Iraq makes a wrong turn in a city: poorly armed Iraq militia destroys much of convoy due to poor training of US support troops. The British against the Zulu at Isandlwana: victory Zulu due to better tactics and leadership. There are dozens of examples were armies with better weapons lost to armies that had better leadership.
Or how about this? You are supremely confident in your wonder weapons, you've failed to train/arm your troops for melee combat. I notice you trains are only guarded by the teamsters. I send my light cavalry (you have none or poorly trained cavalry because like you said your fire weapons make them worthless.) around a wooded area that keeps them out of your view. They fall upon your trains killing your horses and drivers. Then they start burning your supplies including the your spare fuel.
Or because you're a amateur you leave your left flank open. I use the creek/wood area on that side to move a unit of swordsman within 100 yards of your last unit's flank. They charge, you get lucky and turn your formation just in time. You kill/wound about a third of the attackers. The rest are now inside your unit killing with shield and sword, your unit breaks because you didn't prepare them for melee combat.
Or here. Knowing you have lot's of flame weapons. I offer battle in a rain storm. The weather hinders your troops in lighting the pilot lights for their flame weapons. My troops take heavy loses to the weapons you to get workings, but we break your formation and then the killing begins.
Or here: I use smoke screens to mask my deployment. I send in my first attack on you right side. A mixed formation of pike/crossbow. They are supported by medium and light field artillery that splits it's effort between the attempts to suppress your artillery and attacks on your blocks of flame weapons. And it's an accurate fire because of the spotters I have in the balloon. Then come a flight of my gliders. Oh, wow, look at how your flame troops burn when hit with a napalm bomb. I guess you just learned the same lesson many US Marines did in WW2; having a fuel tank on your back is not a good idea. But still you're wonder weapons beat off my attack. But I notice that your fire has slackened on the right at the end as your troops ran low on ammo/fuel. I send in another attack with a fresh unit on the right, while demonstrating a mock build up on your left. You see through my bluff. You keep the left in place and send your reserves to the right, but by the time they arrive my crossbowman are within range, and then the pikes charge at a run. Your troops low on ammo break. They flee to the rear as fast as they can; right into your reserves causing panic in that unit it run also. Your lines on the right have broken, I order a general attack all a long the line to keep you from repairing the right. Also I send in my cavalry on the right to further the rout. By the end of the night your army is destroyed and your head is on a spear outside my tent.
Or here. Because I am not a moron. I know your army has a major range advantage on mine. I refuse to offer battle. I make it a war of maneuver drawing you farther into my country. Further from your supply bases, and I burn everything before I fall back. The country side is empty of food for man and beast. Because you know all you need is one big battle to win you follow. This causes you to be at the end of long supply lines. Which is just what I wanted. I send small bands of cavalry working from hidden supple bases to attack your wagon convoys. This causes you to split off some units to guard those MSR roads. I then attack those small units. But the best is I keep falling back toward my bases shortening my supply lines while your army slowing starves.
Or here: You're army is based on wagon mounted Polybolos. Great, I dig deep trenches like tank traps before my lines. I anchored my flanks on a deeply wooded area on one side, and a wetland on the other. You wagons have no choice but to come up the center. Any because I know you will try to fill in the tank traps I cover them with artillery and put bunkers behind them for crossbowman. Send your engineers forward I will just kill them.
War most of the time is more about leadership and training not wonder weapons. Like I said before it's more about how you use what you have. Nothing you can build post change is going to allow you to open such a large advantage in terms of capabilities to overcome that.
Really which characters where from the military? The only real one I remember is the Brit was a retired SAS trooper in the Clan. The Bear Killers have Havel (a Cpl/E-4 in the Marines) and the sailor construction worker that's not a lot of knowledge. The PPA has the US Army soldier that complains that the "Nobles" acting as generals will not listen to him. Are there any others? If so name them?
Who do you think were engineers? I know the PPA had them because that was one of the protected occupations they looked for. The Bear Killers had one the Larsson father, and he designed their heavy machines that destroy the PPA armored riverships. I don't think the Clan had any. I am sure Corvallis and CORA had some but the books don't name any.
Which historical repeating crossbow are you referring to? The only ones I know of is the hand held Chinese Chu-Ko-Nu and the Greek artillery Polybolos. Ones a artillery pieces good luck moving that through most of the country and the Chinese one was hard to aim and had an effective range of about 80 yards. I think it would be great in the change world but it sure isn't what your talking about.