The idea that a government can maintain all the surfaces of a large city in a pleasant situation is completely unrealistic. It can at most decentralize to to smaller bodies (and get a huge variance of outcomes, what is quite an ok solution too), but São Paulo doesn't have those bodies and is organized in a way that makes them almost impossible to create.

Yeah, maybe the best policy for the city is pushing governance into smaller bodies. But if your goal is to make the city visually pleasant, that's the solution that will take decades instead of years from the alternatives.