Medallions specially are used in several large US cities. Transferable licenses are used in a great many other places. Non-transferable licenses in almost all of the rest of the world. Sanctioned taxis are highly regulated even in places that are otherwise quite dangerous.
There’s still a central dispatching service the vast, vast majority of the time.
Not to mention the medallion system which has government oversight of drivers.
Is that a thing outside of New York?
Medallions specially are used in several large US cities. Transferable licenses are used in a great many other places. Non-transferable licenses in almost all of the rest of the world. Sanctioned taxis are highly regulated even in places that are otherwise quite dangerous.