The “haves” and the “have nots” occupying the same building.
I can see it now, the entire building filled with real live rats after six months. Gonna be a fun time in that place.
If there is some screening device to ensure that the lower-income tenants are working people, this could work. If they fill it up with Section 8 occupants, it will be trouble.
I do think that cities should zone for mixed income development. The larger the city, the more important this becomes. In some areas, it's not just the store clerks and bus drivers who can't find housing close to work; it's the teachers, police, and young professionals. This is not a good way to run a city.
With the rise of the automobile suburb after WWII, the poor became increasing isolated geographically. Out of sight, out of mind is not a good plan. If we expect the poor to go to work, they need to be able to live within reasonable proximity to jobs. And if we want to contain social pathologies and rebuild urban public education, we ought not to dump the poor into concentrated left-behind communities where the problems reach critical mass and create a toxic culture.
Diffusion of low income housing is important. We have 50 years of bad policy to undo. Solutions are highly site-specific and it gets ugly when distant federal or state authorities try to impose arbitrary remedies. But exclusionary zoning is a problem. Here in DC, gentrification is pushing a lot of the poor into the suburbs. Some of our fat-and-happy suburbanites who for years chortled that poverty was DC's problem are getting an education, as inner city neighborhoods get yuppified and gangbangers move out. I don't see any easy solutions, but concentrating poverty is a sure prescription for permanent failure.