This deserves much much more conversation than I'm going to give it at this moment, but hopefully I'll get back to it.
It's common practice to raze low-income public housing and replace it with "mixed-income housing," where some of the units are reserved for subsidized-rent units for low-income families. (The number of units reserved for low-income families is significantly smaller than the number of low-income units razed.) The idea here is to "deconcentrate poverty." The thing is, this is actually about destabilizing poor people.
Assuming that this will alleviate poverty (or help poor people) requires considering poor people as toxic. If you spread out a toxin, it gets watered down and is less potent. But poor people aren't toxins, damnit. Poor people are people, and if you put poor people in a nicer place, that's super, because poor people deserve to live in nice places too. But if there still aren't jobs, education, and childcare, as well as food stamps, welfare income, enough housing units, and sustainable community structures, you aren't helping anything! You're making the poor invisible, which makes non-poor people feel better. And that's not public policy, that's bullshit.
Fuck that noise.