Why don't controllers have the same level of input customization

This is what the xbox elite controller does.

>>384383281
Because one or two preset KB+M layouts are unlikely to satisfy everyone because of the many different hardware configurations and preferences but you can generally rely on plebs to be used to one or two standard controller profiles for the 2 mainstream controller variants. It's a bit more effort for something most won't complain about because PC can rebind externally and console has no standards for quality.

I guess it's usually just not needed. There's not many games that I've had problems with the default controller controls.

Just a guess but it might be easier to design a game around certain control schemes.
Knowing nowadays people, they would probably just start to whine when they change one button and then the whole thing doesn't play well.