[newcomer]

It's a simple question of time. If my memory is correct in german concept of blitzkrieg clearly wrote if they (Germans) didn't won in Russia for a couple of months the war is lost. Because Germans had no such resources like Allies.

As war prolonged, in such circumstances, achieving the air victories in such high rates had not strategic value. It is much useful for propaganda purpose to lifted morale.

Kind regards

Newcomer