S!
Bf109 has always been the glass jawed fighter in IL-2
It was far worse in the beginning whn a single ping from even the small caliber MG's from any angle from even 1km away would spill oil on your screen. It changed, but there are still a lot of things in DM that leave things to be desired.
As a real life comparison Finns removed the pilot armor from the Curtiss 75A Hawk as it was incapable of stopping even a 7.7mm bullet from close range. The reduced weight gave some extra, not much but anyway, climb to the plane. Again on the Bf109 there were many occasions the plane came back after being hit by a Yak or LA and the pilot armor had stopped the 20mm bullet from coming through.
But the root of the problem is that we can shoot and fly better VIRTUALLY than the real pilots. Our accuracy is better, we have this idiotic zoom feature etc. In real life kills were harder to get and in most of cases bounces. So this just shows the flaws in game engine more clearly, and it can be in any game really, not just IL-2. All we do is learn to game the game to survive a tad longer, sad but true.