At it's peak the German army was pretty much broken and unable to counter battery fire due to the lack of ammo as a result of the strategic air campaign.
Which does not at all change the fact that those select Soviet specialist formations showed levels of flexibility almost as good as the Germans had at their peak years in impromptu fires. Of course, I must reemphasize that the specialist formations/units were a select number (many of them guards) that represented the crème (and hence a distinct minority) of Soviet artillery forces, so they did not remotely represent the average.
That's the problem right there, difference in terms. I'm not counting direct fire weapons as part of artillery, meaning indirect fire artillery. If we count direct fire support weapons, then aren't tank guns artillery? They are cannons and even AT guns can and were used for direct fire support.
No, because tank cannons and AT guns usually lacked the same degree of range (which can matter even in direct-fire artillery), caliber size, shell types, and so-on. And in any case I
am also talking indirect fire weapons as well. If tank cannons alone were enough to deal with those kinds of strongpoints, the mechanized armies since 1939 would not have seen it necessary to attach mortar platoons to tank battalions or cross-attach howitzer batteries to tank heavy task forces. A 1941 panzer division didn't have those 24 105mm and 12 150mm howitzers for giggles. A hasty AT defense doesn't take a whole lot of time to setup either: you can pull something like the AT weapons platoon of a battalion off the road march and form a reasonable kill sack with them in a few minutes. Properly emplaced, with keyhole lines-of-sight, the only unit that can engage them is the unit being fired upon (potentially from two or more directions) at which point the remaining tanks have the unenviable choice of either backing off and (potentially) letting the ambushers escape another 10km up the road to repeat the process or (potentially) blundering into a
truly heavy AT matrix and getting decisively finished.
That's one of the tactical problems artillery is supposed to solve for tanks.
Indirect fire support from towed guns generally did not participate in the major mobile advances; having read enough accounts of the 'classic' campaigns of 1939-42 towed artillery didn't really weigh in except during breakthrough fighting,
Then you clearly have not read them closely enough. When Guderian forced the Meuse on May 1st, he had 141 artillery tubes at his disposal. The 1st Panzer Division had the 8 artillery battalions supporting of its crossing. The only reason the Luftwaffe was necessary to tip the balance was because the French had even more artillery then the Germans (174 pieces) and more ammunition. But had the French no artillery (and indeed, much of the Luftwaffe's effort went into suppressing the French artillery so as to allow the German guns to operate more freely), the aircraft would hardly have been necessary.
Depends on the situation and if artillery has had time to deploy.
Generally at least one battery was deployed and available.
Usually for mobile units in WW2 warfare prior to the advent of SP artillery air support did the work of suppressing enemy artillery.
If that had been the case, a lot of offensives would have bogged down much more rapidly then they did as there were many times when air support was simply unavailable for whatever reason. On average, the weather grounded air power for 1 in every 3 days of a campaign. Even beyond that, there were generally not enough aircraft (especially for the Germans who ran with a much smaller aircraft inventory then the other major powers) to cover all of the spearheads. And even with on the ground observers, aircraft could have serious issues identifying enemy positions.
It was unusual for motorized artillery to be in a situation during the maneuver phase of an operation to be able to have the time to deploy and range in against enemy artillery on the offensive.
No, it was quite usual. What was unusual is that
the preponderance of motorized artillery in a formation were up ahead close enough to provide support. But generally enough were up front to give adequate support. The point when not enough were up front tended to councide with the point where the opposition began to rally and logistics began to strangle an advance anyways.
What you describe above is a textbook idea of how combined arms is supposed to function, but prior to SP artillery being available artillery getting into action to support and offensive move by tank or motorized infantry during maneuver was relatively rare and relied more on air support, which could more frequently get into action more quickly.
They ran those exercises with only towed arty available as well. Same result. Hell, in at least one of the exercises I recall (a 2013 Canadian one) the guys with the tanks were also granted air supremacy. It didn't alter the dynamic at all.
I don't think you really understand WW2 if you think the Germans were behind the West and Finns in terms of tactical flexibility.
While I don't know about the Finns, but it's a matter of historical fact that German artillery flexibility was inferior to the Americans. Nothing measures relative flexibility better then the minimum time between the first call and first firing while retaining similar accuracy. For the Germans this was 12 minutes,. For the Anglo-Americans, this time was 2 minutes.
The reason for this was organizational, specifically the fire control methodology. In the German army, the forward observer was tied to his artillery battalion (which was the standard base firing unit for the Germans, splitting up an artillery battalion into batteries and placing batteries under an line battalion is the exception justified only when the line battalion has an independent mission (for example, flank protection) or when the terrain does not permit unified fire control) whenever it moved. When the batteries sets up, the forward observer moves forward to his Observation Post (OP). When he gets there the distance and angle to the batteries are carefully measured. When the observer sees a target of opportunity, he rings up the battery's fire control and gives them an estimate of the range and angle to the target from the OP. The fire control officers use logarithm tables and adding machines to do the trigonometry to convert the two angles and distances to one angle and distance, and to correct for wind, humidity, powder characteristics, etc. Each gun is adjusted so as to attempt to hit the same rough spot (a converged sheaf).
Before Dunkirk, the British used the same methods as the Germans. After Dunkirk, the British changed their fire control methods. By giving every FO a good map and a truck to haul a radio, they separated the direct tie between the FO and his battery and allowed more than one battalion to be called in by a single FO. More importantly, the map, which was gridded off in 1km intervals, was used directly in figuring out how to aim the guns... a simple right-triangle calculation was all that was necessary. The British system was less accurate as no time was spent in individually aiming the guns so the sheaf was never converged. The British felt they could get more guns on target faster compensated for this though.
The Americans used a refined version of the British system that returned accuracy to the system without abandoning the rapidity. An officer heading the American Fire Control Center sifted through all the calls for help and deciding how much to assign to each target, given the observer, the probable target, and the ammunition restrictions. Then the Fire Control Centers used a set of clear protractors and rulers already corrected for wind, powder, etc, so converging the sheaf was possible as with the German system.
As I alluded to at the start of this post, only the best of Soviet artillery forces used the German system and even then only late in the war. Everyone else pretty much defaulted to either pre-plotted fire (or a adjustment of pre-plotted fire using transfers) if possible or direct fire if not.