It seems (from the pitch deck posted in another comment) that I had conflated "ride sharing" with "unregulated use of your car and free time to work for a cab service". It seems I was biased by all the "sharing economy" BS and jumped to a conclusion I shouldn't have jumped to.

ZimRide preceded UberCar. They largely targeted college campuses. Universities would pay them an annual subscription fee to enable ride sharing on their campus.

No links but I'm pretty sure they started off as actual ride-sharing, as in an app to help people car-pool. I'm assuming there was an "a-ha" moment when they realised the laws protecting state-authorized taxi services could be circumvented if you hailed the taxi via a phone app rather than by flagging them down.

Uber started as a better car service and had little to do with ride sharing. Go read their pitch deck. https://techcrunch.com/gallery/here-is-ubers-first-pitch-dec...