I mentioned elsewhere before that all tyre compounds should be decoupled from the upgrade and PI system, and tyres should be allocated based on race type.
That’ll require significant work on all cars in the game though, so it’ll never happen.
Instead, I think races should have mandatory tyres as an upgrade filter/setting, much like how the Mid Engine series limited people to Mid Engine cars or other series limit cars based on their PI or drivetrain.
I’ve put in a suggestion for that on Private Multiplayer, which should hopefully be easier to implement than redesigning the entire upgrade system. Maybe worth having in Featured too in specific events, though I reckon Turn 10 will keep the Open classes “open” as they’re intended to have no build restrictions other than PI.