I agree that is part of the issue, many customers don't care. I think there is another relavent point.
The video of the Ford guy illustrates how companies are competing on improving this tech. If it were mandated, might that be like forcing commoditization? Companies with inferior tech would push it out too soon. There would be less competition because customers would accept the minimal and it would be harder for companies to differentiate. As opposed to now: forward-looking customers with the money can look for the best system which pushes the tech forward.
Apparently Honda couldn't get consumers to pay for ABS and had to install it by default at no extra charge in order for people to have it.