Are you familiar with the concept of induced demand? It's often used in the context of road expansion, in which adding another lane increases the number of trips taken, and hence cars on the road. Often, traffic is often very similar to before the upgrade, if not worse (because the connecting infrastructure was not upgraded).
Demand for trips is elastic, and depends on many factors.
Similarly, if the Tesla robotaxi system is better than driving for anyone, it will necessarily increase the number of trips taken. Whether that's people who prefer to let the machine drive than drive themselves, or people who can't drive themselves (no car or no license), there will be more trips. Additionally, some number of people will take them instead of public transit, which will increase traffic without increasing trips served.
I know in Europe so I do know of walkable cities and how things do find a way with some limitations. We even reduced the amount of roads accessible to personal cars, literally 2 blocks from where I live.
With Robotaxi? Especially with the unavoidable fact (that I kind of don't like) of human driving eventually becoming curtailed with regulations, we can just use all of the existing capability that isn't used by transit, for Robotaxis that don't ever need to park even close to high traffic areas.
Induced demand won't ever overload the much more fluid system, especially as in peak times the prices can just go up a bit, and centers will become "gentrified" in favor of the more controllable Robotaxis way before driving your own car becomes literally illegal. Hell, driving your own car in Finnish cities is already ass.
Demand for trips is elastic, and depends on many factors.
Similarly, if the Tesla robotaxi system is better than driving for anyone, it will necessarily increase the number of trips taken. Whether that's people who prefer to let the machine drive than drive themselves, or people who can't drive themselves (no car or no license), there will be more trips. Additionally, some number of people will take them instead of public transit, which will increase traffic without increasing trips served.