In terms of level 5 autonomous driving, the most common retort I've seen recently is "well, we're going to need special roads with sensors built in, and then it is a tractable problem." There are more than 4 million miles of road in the US; at any given time maybe 2% are under construction. The US Interstate Highway System was built during a boom and the cold war (where the system learned from Eisenhower's WWII experiences and learning from the Autobahn's military utility.) [1] If we're lucky, maybe the interstates will get sensors. But the complexity of re-doing an exit or interchange, which involves dozens of on-the-fly lane changes and cutovers, seems impractical merely to support self-driving cars.
I would love autonomous vehicles for the sake of my children, but I suspect that at best, maybe my grandchildren will benefit.
[1] https://www.fhwa.dot.gov/interstate/brainiacs/eisenhowerinte...