Reminds me of a conversation in graduate school with a developer practitioner guest in a class who was a big proponent of Richard Florida's ideas. Basically, I asserted it was a novelty and that demographic psychographic trends coupled with most every large urban metros municipal government ineffectual structures (high partisan favoritism, unionism, 'inflation educated' and inept workers) would prove so. There's some truth to his theory that creative class initially recognizes the downtrodden undervalued areas, but they do not in and of themselves turn whole cities around simply by living there.
Florida's flaw on the demographic side was there is only so much of the 'creative class'. They, in general, have less 'organic' household growth, and while they create 'trendy/hip' areas they lag in natural growth. That is, they may create a few nice areas that gentrify to the upper socio economic crowd (Single professionals, empty nesters, urban lifestyle yearners - influenced by the last two decades of mass media glorification of urban centers as a veritable potpourri of the 'cool' crowd [Friends, Seinfeld, Sex in the City] etc...' but that once underlying psychographic household and lifestyles are stressed by the higher costs (and safety concerns - real or perceived) of urban living, the organic growth (population growth through reproduction) will predominantly seek out higher quality of life for progeny (as the link Katiana posted so aptly showed) through
lowest total cost for high quality of life, the combination of which is not often found in most urban centers but rather areas on their periphery. Often locations like close to CBD neighborhoods and older inner ring suburbs in eastern and mid west cities.
Cities need to address a combination of variables to be more attractive overall, but that's a whole different thread I know is on C-D, which I replied to in the past.