https://en.wikipedia.org/wiki/Gentry#United_States
Typically gentry are well-off people. Usually, not always, educated. That rings true in "gentrification." There's a whiff of "idle rich" in there that doesn't fit any more, since even the very rich are seldom all that idle these days, now that cotillions and tours of Europe are passe.
I've seen people try to make having artists and the "creative class" take over an area equivalent to "gentrification," but that always struck me as a ploy to say there's a class division that wasn't there. The division wasn't "poor people, typically but not always of color" versus "upper-middle and upper-class people, typically white", but there is a distinction and division, just not one that's based on a callous counting of $. Reducing everything to $ seems crude and insight-repudiating to me. While we need a word for this kind of displacement, I don't think "gentrification" is it; it's already too useful a term for those who dwell on class distinctions while lamenting the lack of extreme forms of social mobility.
This use of the term has always struck me as a crass extension of the original use of the word "gentrification", although there is a similarity at play: One group comes in and displaces another. Typically that "one group", in the case of the "creative folk" is mostly white, but certainly distinct in outlook and mannerisms from most of the surround hoi polloi. There's often a certain snobbery masked by interclass solidarity that's sometimes condescending, sometimes real, and sometimes poseurship.