These medallions are a racket. They are there for municipals globally to earn tons of money. Amsterdam alone earns every year 70 million just on selling medallions. Same time they keep a limited number in game, so it pays of for the taxi drivers to buy into it so they can overcharge the customers.
I'm from the Netherlands albeit the South and speak with a rather strong accent. As it happens to be, once a year I'm back home and I do have a house in Amsterdam. Taxi drivers fucked me over each and every single time. Driving around, giving stupid excuses, not being able to speak the language at all, driving aggressive, I can keep going on. I'm happy these days with Uber, they provide everything in a driver which they should to begin with. And instead for taxi's that they improve their game, they physically attack their competitors, scum.