Exactly even in 1945 German production was on track to match 1944 which was pretty impressive it was a failure for the RAF from 1943-1945 and given the manpower lost in these exercises it was an almost criminal failure
While some places the bombing did slow down certain forms of production (oil, etc.), many other areas it did not help much because it forced the Germans to moved their centralized production to many small production faciclities spread over a large area.
Do you feel the convoy system across the Altantic Ocean was a waste of manpower? Shipping goods by convoys was far more costly in human lives and material than the air bombing campaign!
It was a British economist that first proposed to the RAF, that to destroy seven large railroad choke points would be the most effective way to hurt German war production. The bombing that hurt the Germans the most, was the crippling of the railroad infrastructure! The result was many Me-262s were produced but, could not be mated to the many engines that had been produced but, had no way to shipped the engines to where they were needed the most, at the airfields. There are many examples of this type of problem once the railroads were no longer effective.
Bombers were used as bait! Bait to get the Luftwaffe fighters to come up and fight the Allied escort fighters. If the Allied fighters went down to strife enemy airfields, many experienced Allied fighter pilots would get shot down by flak. (Only a few USAAF 'aces' were shot down by Luftwaffe fighters, all the rest were shot down by flak!) Killing the Luftwaffe in the air prevented the Luftwaffe from being a problem on D-Day or the days after that.
Harris should have learnt from the failure of the London blitz but he was too busy extracting revenge no matter what the cost.
The failure of the Luftwaffe in its efforts to defeat the RAF, was not that they attempted to destroy the RAF but rather, the lack of intelligence and many tactical mistakes.
The efforts to destroy the radar stations and quit before eliminating enough radar stations to put a real hole in the detection network. Destroying the airfields and then stopped before that task was complete. Resulted in the RAF remained an effective fighting unit.
If you analyse the effectiveness of the USAF's campaign over Germany against that of the RAF you will see that American attempts at precision bombing had a far greater effect on German combat efficiency than that of the RAF.
Yes, the USAAF was a little more accurate and.... they paid a higher price in aircraft and air crew losses.
Also keep in mind, until the invasion in North Africa, later Sicily and, Normandy.... there were many days when the Western Allies did nothing to take the pressure of the Russians fighting on the eastern front other than the air campaign!