If you visit the Gilded Age mansions of Newport, Rhode Island, the audio tours mention him somewhat frequently as a collaborator with the Robber Barons in the design of their properties. Considering that much of the intent of their conspicuous consumption was to impress and then marry into the noble lines of Europe, Olmstead's connections to the notion of "gentrification" are, "humorously", at least two-fold.
Seems like a fair deal.