I imagine that autonomous driving drones without any humans on them (essentially delivery robots) will achieve widespread commercial success before ones with humans on them do. Many of your questions would have to be answered very differently depending on whether you count those.

Autonomous driving drones will improve at patrolling and cleaning large facilities, at collecting stuff from shelves in huge warehouses, at harvesting on farms, at freight delivery on railway tracks (this last one not so much in the US, though) and many other tasks. There'll be a trend from specialized to multi-purpose ones, and a growing industry lobbying hard to get access to the common roads.