Bottom line is that you have to cut the free and perk line somewhere. That somewhere seems to be the La-7, Spitfire Mk XVI and N1K2-J.
Sure, you could move it a bit father back and perk those three, but then you'll just have the Spitfire Mk VIII and Typhoon Mk IIb fill their place. Sure, they're not quite as good, but they're pretty dang close. Closer by far than the usage numbers indicate. People just gravitate toward any tidbit extra advantage and that mean a disproportianate number go to the best of the easy planes, leaving the very slightly inferior with vastly lower usage.
So when that happens, do you perk the Tiffie and Spit VIII? If so, do you then perk the Ki-84 and Fw190D-9? Where does it end?