If you're one of the people running a lesser combo, why work harder when your ceiling is lower? The next step would be to switch to the winning combo, and we all know how much people like it when every car is the same. If you want a variety of cars without spec engines, tweaks need to be made frequently. Yes, it can be punishing some for their hard work, but it's a necessary evil if the class is going to have any long-term viability.