I live in Curitiba, Brazil. The municipality proper has a population of 1.8 millions, (3.4 millions if you include the metropolitan area). There are a total of 2250 "medallions" since 1975, and after much effort the municipality finally granted 750 new medallions last year, and is slowly issuing them starting this year. At best, this would mean one cab for every 600 people.
I won't complaint about the quality of the cabs,. They are so rare that they tend to be decent and well maintained vehicles, and their drivers tend to be polite. They are also prohibitevely expensive, and i will use them only as a last resort, especially if my destination is far.
Although Uber has arrived on some brazilian cities, there is still no sign of it coming to Curitiba. And yet the medallion owners are already lobbying to preemptively forbid anyone who does not have a medallion to transport passangers for a fee, basically denying Uber a chance to compete.
Uber might not be an example of ethics, but the market they are gaining is currently being squatted by people who are even worse.
I disagree that Uber is building itself a monopoly. If Uber does not maintain a minimum quality, it's very easy for the regular Uber user to just switch apps.