I think the momentum was there even before impressionism.  As early as Michelangelo's unfinished marbles or Millet.

Marx's ideologies were not the core of what is falsely assumed to be "communism".  Marx explained to Lennon than they couldn't proceed until they had a proletariat.  His own words.  To which Lennon quipped that they would proceed anyway.  Communism was an experiment of the elite, the one percent of today's fame, that among other things wanted something to scare every western citizen into compliance until they had rendered them completely docile.

The reason that this present push is under way by the top of the upper class to eliminate the US middle class, is that said class is basically what Marxie described as the proletariat: those who could possibly mount a successful revolt.

Now, this has to do with artist, and I can tell you since I'm one of those, is this: all art except that which is under their control, will be forbidden but done so by unobtrusive and nefarious means.  Realistic Representationalism poses no threat to their regime since the public is not enriched by it and therefore is not in the least strengthened thereby nor enlightened therefrom.

The beginnings had actually nothing to do with impressionism, but RATHER: it was the onward progression of the great spark of the creative act growing up from it's infancy in the days of the tilers of the Ancient Greek and environs mosaics.  It WILL HAPPEN regardless of what or who happens along, UNLESS, as is the case in the contemporary, Wall Street bottom liners' dominated societies, ARTIFICIALLY held down and placebos such as stilted, boring representationalism or neo classicism proffered in its place ...