...that you can just suddenly force-relocate huge masses of people.  

My gut reaction to that, is, "time to dust off the Second Amendment."  And I think you'll find that 99% of people would feel the same way.  Even the poor in the inner cities will fight like hell to not have their communities broken up, torn asunder, and scattered to the proverbial four winds.  

More reasonable: better development plans; infill; antisprawl; public transport; walkable neighborhoods; relocalization, etc.  Some of which may involve applying torque to developers, but better that than applying torque to the entire populations of metropolitan areas.