They have corporate employees beyond the drivers. They likely have offices and such.

If we're talking total fantasyland, I suppose put those employees to work building a government backed alternative or an open platform to allow smaller companies?

Suppose you had a centralized federated system where states or municipalities or even companies could have their own drivers but it's a common app?

Edit to add you could also have both driver and passenger rate each other and allow both to filter by rating, lower ratings would naturally pay more or less to compensate for the service. I bet in cities you'd have luxury versions of the same services all from the same app, but also cheap shitty services too.