That is not what I observed in Baltimore. I am on the board of a community association that deals, inter alia, with local development issues.
Here, there was no development of any kind for much of the early 1990s. Then the ACLU sued the city for 'warehousing' the poor in housing projects and won. The suit was opposed by suburbanites, especially the current governor Ehrlich ("the exterminator"), because of the fear of the housing project residents relocating there.
As a result of the suit, the worst projects were demolished and replaced with Hope VI housing, which is a mix of subsidized and unsubsidized units - to remove the concentration of poverty and the stigma of living in a project. One cannot tell just by looking which units were subsidized and which were not. As far as I know, most residents were pretty much happy with that arrangement, because it gave them nice homes and helped getting rid of the worst criminal element that plagued the old projects. The residents tend to be single moms and the handicapped.
As far as I can tell, most other development in Baltimore is based on the renovation of vacant housing, which is in abundance, and does not involve any displacement (except occasional vagrants who may squat there). Maryland provides tax incentives for renovating historical areas, and that is what's driving this effort. The catch is that the existing structure must be preserved, not demolished.
New houses can be quite pricey for Baltimore - $300k up (but that is inexpensive by the DC standards) are being build mainly along the waterfront, but these are mainly vacant formerly industrial lots. As far as I can tell, Baltimore aggressively tries to attract new residents, especially from the DC area, as a part of the urban renewal program, and housing development (aka "gentrification") is a big part of it. The underlying logic is to increase the city tax base to pay for public services, which are notoriously underfunded.
My observation is that the only folks who raise stink about this are a small group of looney self-styled 'activists' who routinely oppose every change (I know some of them and seriously think they are in need of psychiatric help) - but they do not represent anyone and, I suspect, are sometimes quietly supported by the suburban interests who like the urban/suburbs segregation.
Wojtek