I think during/after the Vietnam War was the rot finally beginning to show in the tree.
It may have started as far back as WWI. So many soldiers rejected God because they were given no answers to explain the Great War. Then there was the sexual freedom so many soldiers experienced overseas. Life is Life and it happened, despite the folks back home wanting to belief all their boys/men were chaste and honorable.
Are changed greatly at that time, going from accepting what was beautiful to various Isms. So many folks back then, were like folks today; not wanting to admit they were looking at trash, because they wanted to fit in with the current crowd.
I think your idea of Academia’s being the front point, though is an extremely good comment.
And to think, even today, there are folks who thinks going to College just to go and leaving monies to Colleges are a good thing. I realize there are some professions where College and further education are a must. For all others, though, they may as well stand in the street and throw their monies out hoping it does good.
The song, "How you gonna keep 'em down on the farm
after they've seen Paree?" was an indication of the result
of exposing soldiers to big city morals in Europe.
The Lost Generation referred to writers who left the US
for the greater freedom of expression abroad, not any
shift in American culture itself.
Art did change, largely from Art Nouveau to Art Deco,
superbly represented in the Chrysler building in NYC.
The increased use of cameras drove art towards being
non-representational. When you think about it, an artist
who could represent reality perfectly was at the peak
of his career, doing something a camera did trivially.
When representational capture was perfected, how were
the new crop of artists supposed to break new ground?