Spoken like someone that lives in a high-density area. Switzerland is 223 per Km2 while the US is 37 per Km2. In the EU, only Finland, Sweden, Latvia, and Estonia have a lower population density. There average across the EU is 109.56 per Km2. GB is 280 per Km2.
Solutions to transportation in the US need to factor in the density and account for the low-density areas as well. Politically, those low-density regions are, IME, the ones most likely to fight against changes that would move towards mass-transit because they feel like they are being ignored.
Beyond that, SDVs and Mass-transit aren't at opposition. Busses can and should be SDVs as well. As mentioned by another poster, small handicap-accessible SDVs that do point-to-point transport are _better_ than mass-transit. If vehicular mass is a concern, with ubiquitous SDV integration into an urban transit system you can and should design purpose-built transporters with lower mass. With central EV charging and remote power generation you are already moving the pollution point to a smaller number of locations that are easier to optimize and monitor.
Really, these people seem to be saying "We don't like this, so you shouldn't be allowed to do it" and then they use flimsy excuses as justification. That makes them just like all the other people that want to force their world-view on me. Maybe instead of doing that they could spend all of that energy on moving the needle on the core issues that are possible in the short term and will make a difference, like moving to green renewables for power generation.
Sorry if this seems overly cranky, but it's frustrating to see people that think interfering with SDV operation is a 'good thing' in any way, shape, or form.