I think we do see a lot of this today: Uber and Lyft already have incorporated ride sharing and I use that option every time -- when I'm in a city I frequently have another rider or two. I'm curious to see how this will increase as ride sharing density grows.

I think people avoid public transit because it is necessarily slow due to the multiple stops. They may also avoid it because it is too accessible. Sharing a vehicle with other commuting professionals is a vastly different experience than what you'll find on most public transit.

Because right now, this class of service is broken up in ad-hoc service companies, none of which have been incentivized to become a regional rental pool.

Consolidate taxi/minibus/event bus/medical&elderly ride/mass transit into a pool of vehicles available 24/7 with resources for surge times/maintenance/cleaning etc, and this will become the norm easily enough.

Then it's just a question of who operates and at what cost?

Various towns have looked into this sort of thing. [1] It doesn't seem to be very common however.

[1] https://www.theverge.com/2018/3/12/17109708/via-arlington-te...