Why do I say they are a mafia? Well, for a start, not a single new licence has been issued by the authorities in the last 30 years (more or less). If you want a license, you have to buy one from a current Driver at an astronomical price. In Madrid some people have paid more than 300.000€ for a taxi license, often going heavily into debt. These drivers then have to work extremely long hours without taking any Holidays to pay off their debt, while a few families have dozens of licenses in their hands, not having to work at all as they prefer to have 3 guys driving around 8 hours a day each for a minimum wage pocketing enormous profits. When they die, licenses are automatically inherited by their children, thus perpetuating the monopoly.
Of course, this is all starting to backfire on them as it adds to decades of overpricing, regular passenger-scamming and rude behaviour (which they could allow themselves thanks to the lack of competition). People have given a great welcome to Uber and after the mafia has shown ist true face les and less people are using taxis.