Unless it's changed over recent years my understanding is that in many cities there was a high barrier to entry for taxis in the form of licensure. In some case

Unless it's changed over recent years my understanding is that in many cities there was a high barrier to entry for taxis in the form of licensure. In some cases only a finite amount, causing sky rocketing prices. From what I've read it's similar to how some areas in the US have limited alcohol licenses (usually a per capita system in that case iirc), often they are then auctioned off for higher and higher prices where permissible.