Robocars most certainly exist. They’re probably about 5% of car traffic in San Francisco. I’ve not taken one yet (taxis/ubers/Waymos are mostly impractical with a young kid in the US as you must use a car seat unlike in most European countries) but as a pedestrian they seem mostly a safer than other drivers. As a driver I expect they will eventually induce gridlock but the city can always create more bus lanes.

Portable booster seats are pretty small. I can’t see it working if you have a kid younger than the booster seat min though. Only a few states have strict rules here, Washington and California being a couple, although I think California has a taxi exemption.

Robotaxis ≠ robocars.

The robotaxis that do exist only do so in very limited places using very expensive technology (including off-shored service center for intervention) that is not available for the public consumer markets.