https://en.wikipedia.org/wiki/List_of_automated_train_system...
Regular people drive cars out of necessity to commute. Cars are ubiquitous.
Which market was easier to sell to investors?
People should get paid to drive their car to work. It's dangerous, has high liability for them in case of injury or litigation, and in any case they should be compensated for even driving at all.
That's because people like me can only ride bicycles because being such terrible drivers. Unless taking an amount of stimulants niggardly shrinks will never prescribe for the specific task of driving, driving would put many other people at risk and lead to an accident a day, whereas on a bike the maximum death toll is myself. And I suck up the accident with my adrenaline, my body, and the bike frame. Injury without guilt.
We already have automated (no staff in train) metros (Paris' 14, Paris' 1, soon Paris' 4, Paris' Orlyval, Rennes' a/b just for the ones I've used)
I remember there was a prototype bus (12 person size ~) at La Défense - with a staff always on board, and I see that now there is "EZ10" in Toulouse, but I remember seeing also other lines as well. I'm pretty confident there are many all across the world.