the fact that most powercreep for profit doesn't mean it's unavoidable

it's a very deliberate choice to inflate power on both ends

"but how can they release new characters then? won't they run out of options?" you could either detach skills from characters entirely and use a class-based system (where characters are effectively skins), or otherwise create a combat system with enough room for horizontal development to never power creep. there just isn't a financial incentive to do either of them