Joe, welcome to the very conservative world of general aviation, where it takes a very long time for new technology to become certified, trusted and established (and not necessarily in that order).
I know one has to have more reliability in an aircraft but the full authority electronic throttle in your BMW (including Mini) is going to kill you and probably several other people if it fails open so basically it doesn't!
In an aircraft, speed (and altitude) is life. In a car, speed kills. So if given the choice, an aircraft engine design will fail towards a "high power" setting, whereas a car engine design will fail towards the "no power" setting. The idea for an aircraft being that if you have such a failure, the engine will develop as much power as possible so that you can climb to altitude, or go into a climbing cruise, until you've come to an altitude and place where you can glide to a safe landing, hopefully at an airport with long runways. At that point in time you kill the engine.