Require corporations such as Uber to provide free service to people who can't drive, such as disabled or senior citizens. This would drastically expand accessibility for those people. Unlike paratransit, which is often abusive and/or unavailable, Uber is designed to provide a ride to and from anywhere on a moment's notice, and has a rating system for drivers. A corporation is big enough to absorb the cost of accommodations such as wheelchair-accessible vans, whereas an individual taxi driver usually is not. People who are blind, Deaf, walk with a cane, etc. can typically ride in a standard car. When disadvantaged people are forced into a service ghetto, the service tends to be so bad that some of them would rather do without than be abused. But when it's the same service used by everyone else, more advantaged members demand higher quality.
With Uber required to provide a social good, that would remove some of the imbalance straining private taxis to keep up, and it would also slightly offset the customer base, reducing competition.