The Luftwaffe training was meticulous, there is no doubt about that. However, it was extensive and was not providing pilots fast enough as the war wore on.
In regards to their "lots of aircraft", no...they did not have "lots" of them. They started the war with 737 bombers, 614 fighters, 134 dive bombers and others for a total of 1,928.
How can one reasonably justify starting a war with fewer than 2,000 aircraft?
The rest had less... all is relative.
By the time of the main campaign in the west they had close to 3.000, most of them newer and better than the opposition, with better tactics and training.
They did of course FAIL to adapt their training and production programs to make up for loses (usually by screwing up with the next gen aircraft, Me 210, He 177), but, I am responding to the quoted post, 4-engined bombers use LESS crew and LESS materials when considering bomb tonnage carried, they are cheaper...
If the LW had replaced 1000 He 111 with a 5 crew and a 2t payload, with 500 4-engined bombers with a 6 man crew and a 4t payload... you would have the same capabilities and save in aluminum, crew and fuel for training... or make more 4-engined bombers for the same expense, IIRC Kesselring mentioned they could have gotten 2 heavies x 3 mediums.
A good trade if you ask me.