Americans don't take the bus because they don't want to sit next to the type of people who can't afford a car or get a driver's license.

What would make Americans take buses would also be if they just stopped openly hating homeless people as a matter of life.

And if you save a lot of money, you can improve all of those.

But that is more the cost of other stuff. I bet the difference in costs between driver and self-driving vehicles that are as reliably and safe as bus drivers is not that much. Mechanics etc... would still need to exist for driverless vehicles just as much. I think creating electric busses is much needed, without dumping lots of money into making them autonomous at the start.