Don't tell me... you are a man? I guess so. How many middle class women and above want to ride SFMuni after dark? Few.
The future of self-driving taxis is women (customers) who want to live in a big city, but don't want to ride mass transit, nor ride in a ride-hailing services (Uber, etc.) with a human driver... because most drivers are men.
This kind of gender politics is tiresome. You could easily point out that for women public transit is untenable after dark instead of bringing the OP’s identity into it.
I imagine that Uber can also be somewhat sketchy but with a different risk profile (getting into the car with a stranger, often a man, and needing to trust that they'll drive you to the right location), which means that self-driving taxis would be a potential safety upgrade over that as well.
Uber and Lyft both provide an option for women to request female drivers. In both cases, they say they can't guarantee it and that they may end up matched with a male driver. (In Lyft's case, they group "nonbinary" with women.) I suppose you could cancel if you see it's a man, and if that's rare enough, maybe that's workable. (Though, it seems, that would happen only if there aren't any female drivers available, and thus you'd have to fall back to other transportation.)
https://help.uber.com/en/riders/article/women-preferences-fa...
https://help.lyft.com/hc/en-us/all/articles/9030680293-Women...