They will ovbiously reach that level if un-perked, or they have some other unique reason for being perked. There is no need to leave them unperked for a while to see. Take the F4U-4 as an example:
The P-51D is already one of the most common planes in AH, usually accounting for roughly 10% of the kills in a tour. That's enough usage where some people already feel this airplane needs to be perked. Now compare it to the F4U-4. The F4U-4 is better, often MUCH better, in every aspect. If you left the F4U-4 unperked it would indeed see excessive usage. So it's perked.
The Ta-152 is perked not because it would ever dominate the arena (it obviously wouldn't), but because at high altitudes it is untouchable. In other words it ruins the balance of the arena. There is nothing except a jet that can compete with it over 30K. If there were other planes with such good performance up there, then there would be absolutely no need to perk the Ta-152.
The reason the planes like the P-51D, 109G-10, FW-190D-9, Spit IX, N1K2-J and LA7 don't need to be perked is because they balance each other out and don't dominate the arena. None of these planes has a whopping advantage over the others and none of them sees excessive usage.
Perking these planes to make, say, a P-40 more viable would be using the perk system for something it isn't intended for. That wouldn't be perking a plane because it doesn't fit in with the rest of the arena; it would be blanketly perking a group of planes to force people to fly different ones. And that, IMO, is not what the perk system was designed for.
J_A_B