It's not a common problems in Austin at least. You (a property developer) buy a single home in bad shape on a big lot in the city. Then you redevelop the single home into 20 apartments, greasing the wheel appropriately (of the local government) to get the needed rezoning and permits. No one else can do this because they don't have the connections and monetary resources you do. You pocket the increase in value of that property (minus the cost of grease) by selling it off as "condos" which have dubious maintainability going forward. You never lived here anyways, you have a ranch in Bastrop.