The problem with busses is that anybody of means doesn't like taking them. Too many other people's stops and what not.
But with a bus you could enter your destination (as would everyone else on the bus) and it would pick a few key optimal stops. Have the phone buzz when it is your turn to exit.
Have a large party? It wouldn't cost a ton to just schedule a pick up and a bus comes over 1 block, picks you up and then continues down town or wherever else it was head.
You could optimize bus routes on the fly. Big sporting event get out? You could easily re-route a ton of busses and then put them back on normal routes.
You can easily make busses full electric, NG-hybrid, diesel-hybrid, etc which makes it more efficient. If it works I can see cities like London and NYC going completely driverless. Rail into the city. Automated busses and subway in the city.