FSD is really easy for 99% of driving, its the 1% that will be the problem.
In order for it to work, it must be 99.9999% reliable, which is a long way away.
It come down to the car knowing how to deal with "judgement" that is really difficult, say for example you are in a construction zone, and they have a small one-lane detour on dirt on side of road with a signal person there, how will FSD handle that?
Also, how will FSD handle a 4-way stop, we as driver know to look and gesture/nod to each other at 4 way stops to signal who goes ahead. The FSD car will probably come to full 3-second stops as well, really annoying everybody snce we all know that you shouldn't really do full stops for the sake of traffic flow (I expect to get flamed for this but you know its true)
Maybeonce all cars are FSD we can design roads accordingly, but that's at least 20 years away.
No way robo-taxis are coming any time soon! Except perhaps in very controlled environments