I'd try approaching this from the policymaking prospective.
As soon as the technology is there (assume it is possible), in my opinion, we are very likely to end up with the following interests becoming dominant in the decision-making framework shaping:
- car companies willing to sell more cars,
- banks willing to extend more car loans at an unprecedentedly low rates (to private owners or private shared fleet operators),
- construction companies eager to build more roads than ever,
- politicians willing to get rid of the headache of dealing with all the 'political difficulties' associated with development of (and running) any mode of transportation that is not cars, and willing to sell to their constituents something that is shiny and innovative,
- lots of people being genuinely happy with cars becoming more available to them (both in terms of lower costs, and zero barriers presently associated with individual suitability for driving)
All these pressures are not new, are already there, and will be emphasized with cars becoming more affordable ('affordable', car loans involved). Another round of urban destruction and mass automobilisation under these circumstances appears to be a scenario far from being impossible.
There are, of course, more positive futures for humanity to pursue - ones where the AV technology gets its first full deployment across all modes of public transportation (where it should be computationally easier by default) which enables further service expansion and street space redistribution towards sustainable mobility, and, eventually, phasing out cars in cities entirely (or almost entirely).
However, there's no guarantee that would happen - too many policymakers are oftentimes more motivated with big (and quick) money rather than anything else, and I don't see enough lobbyists working on this version of our future.
All tech comes with opportunities. It is not the tech nor the worst case scenario that interests me. It is the governance, regulation and policy that maximises the public interest while balancing the need for vendors to get a return which together delivers the best public value outcome. AVs can solve many problems. And as San Fran has found, if allowed on streets before capable, can cause many problems. With something as incredibly complex as automating a vehicle in a mixed use environment there will be multiple false starts. The Gartner Hype Curve is close to the trough of despair for investors in AV, but every learning and failure is a gain towards something that can be made socially useful. And it is always important to point out that access to a car is necessary for many people to thrive in their daily lives simply because the economy has shaped over a century around presumptive automotive access. No government can afford to close all those gaps with route-based PT, but it could potentially overcome inequity through access pricing and a transport card for those in need with a fleet of competitive AVs to buy service from. The tech is a very long way from ready, even in a dry and well maintained city like San Diego, so we have time to get the public value settings right...