They already can. Police will simply crash your car if they feel like it by using their car.
Either that or I could argue we already have a killswitch like that - suspending your license - if I also go along with the idea that the cop won't flip your car when you're not running from them because that's also illegal.
So either we have a world where the system works or where it doesn't, but unfortunately we have both.
Except for all the times it's happened when people weren't running from them?