Not sure why you found that short-cut characterization so objectionable.  Sure, there's a more thorough definition of gentrification (that surely doesn't need to be spelled out in every article discussing the issue).  "Hot market" may be a bit of a snarky way to describe it, but it's not inaccurate either.  The main root cause of gentrification is property values going way up, such that long-time residents in old neighborhoods sell and move out to cash the profits, while wealthier people buy and move in (often rebuilding/remodeling in the process).  

That IS a hot market.