Most people never use the function keys because it's too difficult to figure out what they do. So on many keyboards already you can't use the f1-f12 keys without a modifier, otherwise you get multimedia functions that are printed on the keys.

Having the functionality shown on the keys would help.

Also Apple is probably trying to create something new to get people to buy the hardware, that's how it works. Apple does try harder than most to make their features actually useful though.