Just to illustrate the point with fake numbers..
If 90% of drivers are doing the gig thing, maybe they’ll be driving Uber an hour a day on average. Then if 10% of drivers are doing 12 hours a day, most rides will be from the small minority of full time drivers.
It’s exactly the same as the experience most people have that flights tend to be overflowing with people, when the airlines claim many flights are totally empty.
Students, retired people, and my favorite was a guy who would take 1-2 trips on the way home from his job to put into a travel savings so he and his family upgrade their vacations.
Every market is different though, I can definitely believe that the situation could be very different in California.
I'm sure there are tons of fulltime Uber drivers, especially if you live in a city where cab drivers have made the switch. I live in the suburbs, and I've never met a fulltimer.
One of the Uber drivers I had when visiting New York rolled up in a expensive German SUV (Mercedes IIRC) and was very well dressed.
Chatted and found out he was a lawyer by day, but drove Uber in the evenings when he was bored.
He didn't _need_ the $10-12 bucks we paid for the trip to the restaurant, but he did appreciate the chat.