The would have their asses kicked every single time, would be an unfair situation too.
So learn how to play on kb/m if you want to play on the pc, and learn how to play with a controller if you want to play on console.
I'll put it this way, what if consoles did have support for keyboard and mouse in the demo of a game and you bought it specifically because you thought it was going to be in there only to find out that it was taken out of the final product?
All of your points still carry no weight and are totally irrelevant.