I fundamentally believe that car dependence is built into North American suburbia (how much of this is by design is another matter - plenty of people claim that

I fundamentally believe that car dependence is built into North American suburbia (how much of this is by design is another matter - plenty of people claim that the car and oil industries have been making sure their products will continue to be in demand for decades to come). Public transport and bikes are not feasible in Houston or Los Angeles, due to low density and hostile roads. Going back to your argument, I believe all of this would also be possible with cabs, from a user's perspective the only difference between an autonomous car and an Uber might be price (over the long term) High speed rail between large agglomerations like SF/LA seem like obvious improvements,but seem impossible to build in the USA.