FF, by your own statements, one could also say that the perking of the chog took all those pilots from 1 plane type and put them into 4 or 5 others. I would call that an increase in diversity. The chog didn't go away; it was never removed, and no one forced those guys into different planes. The simple truth is, you guys who switched weren't willing to risk even the token perk price to continue flying it. The diversity was always there, but the pilots limited it.
If everything is perked, everything will be flown as the few perkplanes are currently flown by the majority. To an old hand whose had an account for years, losing a few thousand perks in a week isn't a big deal. To a relative new comer with only a few hundred or thousand perks, losing all of them and being stuck in an a6m2 for most of a tour would not be all that fun.
Perking everything, or everything past year X, would only limit the newer players, not the vets. I know you guys want to face a bunch of n00bs in early war planes who can't put up much of a fight(well, I do anyway), but that would be both horribly unfair and an extremely bad business move for HTC.
I wanted to add, as the tone of the post seems stern, that I'm not trying to poopoo anyone's ideas. Nothing HTC can do will ever restore gameplay to the way it was in early AH1. The players could, at any time, forego the late war planes and start flying nothing but a6m2s. However, you can deduce that they don't want much diversity, they don't want to fly different planes. They want fast and well armed, and they want to fly in packs. Gameplay has never been up to HTC, its always been the community's responsibility. Remember when the ENY limiter was added to promote balance? What happened? 2 or 3 squads started rotating, and a few of the lone wolf types started moving around, but mostly we just got hordes of B ponies and 205s instead of Ds and 190s. Human nature is just that, and HTC can't change it with some lines of code. This is the path he chose for the game, and this is the one we followed him down.