Ignoring wifi as a poor use case here(you'd likely use something with much less interference and better latency), RF will still usually have more latency than a wire. It's more prone to interference from other random devices and even other cars. Canbus is typically shielded, which you obviously can't do with something relying on radio.

Then you have physical interference...imagine all your warning lights come on, wipers come on, and radio cuts off because your wife put her Stanley in just the wrong spot.