I'll take the bait: Yes an external cab company should be able to come into SF and compete with the local firms. The SF regulations have expressly been rigged to support a local cartel and are morally illegitimate.
You may think that an external cab company (or Lyft) should be able to come into SF and complete with local firms but you also apparently agree it is illegal. I personally consider it equally morally illegitimate for individual actors in a society governed by the rule of law to decide which laws and regulations "work" for them and which ones don't, then to disregard those they don't like. And in practical terms I think it is irresponsible for a group of people with one goal -to make money- to set up a company which they know is breaking the law, and to convince a lot of people to join them in breaking the law (their drivers) and creating ridiculous contortions that allow them to pretend not to be governed by the rules ("the donation thing" e.g.) when everyone knows they are a taxi service, plain and simple.