Pass all the laws you want, there is simply not enough wealth (i.e., not enough material and skilled labor) for everyone to live in a house that meets building codes. No matter what you redistribute (note: India has very low inequality [1]) or demand from people, you can't squeeze water from a stone.

[1] Nominal inequality is low, but inequality of living conditions is high. This is the exact opposite of the US, where the rich have a PS3 and an XBox, and the poor are stuck with only a PS2.

Brazil has a minimum wage. If it's not enforceable maybe that's because it's based on wishful thinking, pandering to those with an unrealistic mental models, rather than what's sustainable.

These 'vast marginal neighborhoods that no one wants to live in', they are empty ghost towns because no one wants to be there? I don't think so. And the favelas would just disappear if the firm-handed authorities were just a bit more insistent everyone get paid more (or nothing at all!)?

Rich societies can afford nice neighborhoods and rigorous building codes. Societies get rich by accepting every opportunity for voluntary coordination and incremental improvement. Societies stay poor by enacting showoff policies that appear generous but destroy more productivity than they enable, satisfying the aesthetic hopes of comfortable do-gooders, but trapping the really poor.

Except this is simply not true. Germany, where workers enjoy generous terms and privileges even for Western Europe, has no minimum wage, and its labour unions vocally oppose introducing one. Countries such as the US and UK with minimum wages have higher unemployment, and things are more precarious even for those in employment.