Nonsense. You start with driverless cars that can use existing infrastructure with everybody else, then as the density of driverless cars goes up over time, you take advantage of the other economies that emerge. At some point, probably decades later, eventually society will simply ban driverless cars, but you don't have to start there. There's no need for a "big bang" event.

By the time that happens, the "poor" won't have to "replace" their car, because they'll already have dumped the expensive rust-buckets for time-shared rent-a-cars. It's the rich that will be the last holdouts, not the poor.