I haven't researched the rationales behind taxi protectionism laws, so I can only offer conjecture. Two two reasons I can imagine we have such laws are traffic congestion control and accident liability.
On the surface congestion control seems far easier to implement (especially in a pre-mobile phone context) via restriction of medallions. I don't have arguments one way or the other as to the necessity of congestion control because I've only rarely experienced large cities (NYC, Chicago, London). I believe they are popular for various reasons, but I am not familiar with the arguments for or against.
Determination of liability seems like another obvious reason for a medallion monopoly. Presumably taxis are a higher risk pool for insurance claims, due to the presence of multiple parties. It's unclear to me where the liability falls if an Uber driver is in an accident that mortally wounds a passenger; will their standard insurance (that presumes a certain risk profile) cover the claim? I'm simply not familiar enough to definitely comment, unfortunately.
The latter argument holds more weight with me, but I'm sympathetic to arguments against it.
On the surface congestion control seems far easier to implement (especially in a pre-mobile phone context) via restriction of medallions. I don't have arguments one way or the other as to the necessity of congestion control because I've only rarely experienced large cities (NYC, Chicago, London). I believe they are popular for various reasons, but I am not familiar with the arguments for or against.
Determination of liability seems like another obvious reason for a medallion monopoly. Presumably taxis are a higher risk pool for insurance claims, due to the presence of multiple parties. It's unclear to me where the liability falls if an Uber driver is in an accident that mortally wounds a passenger; will their standard insurance (that presumes a certain risk profile) cover the claim? I'm simply not familiar enough to definitely comment, unfortunately.
The latter argument holds more weight with me, but I'm sympathetic to arguments against it.