Earlier quoted context omitted.
There are fewer of them and they are more efficient, running at higher passenger utilization.
This can’t be true. Taxis often run with zero passengers, whereas a private car never does.
* Judd Cramer, Alan B. Krueger, "Disruptive Change in the Taxi Business: The Case of Uber", 2016, https://www.nber.org/papers/w22083
and
* Y.M. Nie, "How can the taxi industry survive the tide of ridesourcing? Evidence from Shenzhen, China", 2017 https://www.sciencedirect.com/science/article/pii/S0968090X1...
Both seem to confirm that ride-hailing has better utilization rates, though Nie qualifies that--e.g. sometimes too many private cars might turn out. However, at least in San Francisco all the licensed taxi cabs also use ride-hailing apps, so their utilization should be at least as good as unlicensed cars.
The real issue with ride-hailing is induced demand. In places like San Francisco public transit took a huge dip, and ride-hailing simply isn't anywhere as efficient as mass transit. Studies have shown that ride-hailing has contributed to a substantial increase in traffic and traffic delay: https://advances.sciencemag.org/content/5/5/eaau2670
Ride-hailing can even be worse than personal cars because a personal car has a 100% utilization rate at minimum, whereas the average utilization rate for ride-hailing, even accounting for multiple riders (e.g. >100% for any particular trip) is Ride-hailing only pencils out for the last mile--to and from transit hubs in a local vicinity. But too many people take it to cross town. It's hard to blame ride-hailing companies, though. Cities need to be build more subways. Perhaps companies like Uber, if they were allowed to build subways as cheaply as The Boring Company can do (i.e. small diameter tunnel, though still larger than London and Budapest; no red tape; no extravagant stations) and to capture the revenue, would invest the money. They'd finally be able to ditch drivers, too, because driverless cars will probably only ever work, if they work at all, in moderately dense residential areas.