I’m not particular versed on the topic but I would have thought the primary motivators are a) increased safety (in the case of cars and transport) b) freeing up countless lost hours commuting for more productive work
Regarding b) -- it's unclear how much of current(and potential) workforce employed in this kind of work can successfully transition into other fields of work.
Not much better, probably slightly better than autonomous cars because the number of vehicles is smaller. But most people prefer to sit in their own cabin. Autonomous cars give you the best of both worlds. You can decide who you spend your time with or hear music as loud as you want, but are also free to do other things than driving. It's cleaner (or at least your own dirt), and you don't have to carry anything around, as you can store your stuff in the car.
Public transport can come in very different forms. If there's demand, PT operators can build private compartments, seats with increased comfort, etc.
Practically nobody would say something like “I’d like to share a cabin with strangers” or “I prefer to walk to a bus stop and wait there for the next vehicle” or “I like to carry my stuff around instead of just leaving it in the vehicle”.
Plus in most areas NIMBYs also block expansion. When I was in my teens attending community college back home, it was regularly discussed how there was work ongoing to expand our local public transit rail so it would reach the campus. At the time it was 3 hours on the bus (w/transfers) to reach campus so I had to get a ride or drive myself (~20 mins) to get there. ~10 years later the expansion still hadn't happened because people were fighting hard to block it.
This is the bit that worries me the most. If autonomous driving makes longer commutes comfortable then people will move out further and further. Even with EVs this will be a lot of extra energy used for transportation.