Mostly because there is a vote threshold of 5% to get seats, but due to the assembly consisting of 57 councillors, once you make it past 5% you're guaranteed three seats.

I fail to see the point of a 57-member assembly when the councillors are elected on party lists in a single district with a 5% threshold. They might as well have 19 seats. That's a 3x bloated collection of parasite councillors.

If I were King, I would make each of the 21 districts of the city elect two councillors on personal votes with single transferable voting, and 15 on city-wide party lists to improve overall proportionality.

Bush is a symptom, not the disease.