Earlier quoted context omitted.
I find this a very weak argument. You're essentially saying that we have to limit car usage because too many cars cause congestion. Congestion has an explicit cost (wasted time) even if it is not priced in with some artifical time-of-use payment. Ultimately people will get onto the road one way or another if they need to get somewhere at a set time. So by limiting cab licences, all you are doing is limiting the mix o…
The idea is not to reduce cab counts to the point where people call towncars instead; that's likely a worse outcome, because the towncar spends only ~1/3 of it's time full: the other 2/3rds are spent driving to and from the towncar's parking space. Ideally cabs would spend near zero time driving around empty. Today this is solved by medallions, imperfectly, but tomorrow this can be solved by technology. What can't be…
There is no person, committee or even algorithm that can set the correct supply better than a freely trading market. This has been known for a long time.
>In some respects, this is a natural monopoly.
No, it's an artificial monopoly. What we are talking about here is exchanging rides for money. That is the market - paying someone to drive you on a point-to-point basis.
If the market were left to it's own devices, and the only regulations were around traceability, security and the usual laws against blackmail etc, then you'd have a floating market with different prices per time of day and per trip. This would actually work against congestion by pricing it in.
Instead we have a central government committee deciding supply by whatever they use, and fixing prices. The natural outcome of fixed supply and fixed prices is sub-standard service and a shortage of available product. Which is exactly what cab users everywhere experience.