I'm going to speak out of my ass here, but I would venture to say that all cars are governored to *some* extent. Now whether is to protect you or the engine, or both is up to specific cars/brands.
I really see no reason why any person needs a car that will do faster than 100-115 MPH stock from the factory. I'd be willing to agree to have a governor of some sort put on my car that limited it to say, 90 MPH so long as I could get some sort of rebate back from my insurance company. That would probably never happen, so it's really sort of a moot point.
But anyway, for 99.9% of the population, I think that regulating a car to 100MPH wouldn't be a bad thing.