There's a selfish case for the wealthy to care about this: rising tides lift all boats, including theirs. When the bottom 80% are struggling with housing insecurity and desperation, the consequences don't stay contained to poor neighbourhoods. San Francisco seems like a good example—the visible decline in public spaces, safety concerns, and urban decay affect everyone who lives there, regardless of income. The wealthy can insulate themselves to a degree, but they can't fully escape a deteriorating society. They'd be better off in a city where everyone has a baseline of stability.