But I find it rather amazing how every municipality around the world is rushing to the defense of existing taxicab services.
That is because every municipality went through the time when there was no taxi regulations.
Bingo. Obviously in the larger cities there is going to be somewhat of a profit incentive because they have the benefit of scale. The county I live in is relatively rural but it neighbors a big metropolitian county. There are taxi regulations for all the reasons you listed. From a financial perspective the cost of the licenses barely covers the cost of administering the program. Time was they thought about doing away with the program because it was costing more than it was taking in. The county commissioners had residents packed to the rafters demanding that the program stay in place because many had memories of the unregulated world just 15 years prior. In years that the program doesn't self fund the county makes up the difference.