Low rent neighborhoods next to a desirable location don't exist, though. What happens with gentrification is that locations become desirable, and because of in

Low rent neighborhoods next to a desirable location don't exist, though. What happens with gentrification is that locations become desirable, and because of inability for them to grow people "spill out" into adjoining areas. If you could build housing right there (i.e. taller buildings, denser neighborhoods, subdivisions, etc...) the problem wouldn't have happened in the first place. But NIMBY rules prevent that to protect existing owners.