Progressivism started before the 20th Century. Teddy Roosevelt was a progressive. Wilson was a progressive. Progressives are communists by another name. Communism has been around since Marx and Engels in the 1860's.
Read up on Antonio Gramsci, and "his theory of cultural hegemony, which describes how states use cultural institutions to maintain power in capitalist societies." Gramsci's theories were part of the Long March Though the Institutions, where progressives worked overtime to change/destroy cultural institutions, as we see BHO do on a regular basis (see: BHO's utter disdain for our military and his destruction of it as a cultural institution). Destroy the culture and you destroy the society. Destroy the society and anything can happen, including the populace clamoring for Big Daddy Government to save them. And that is exactly what the progressives want, to be the knights in shining armor riding in on a big white horse to save the day -- and institute totalitarian policies like green energy crap and climate change laws based upon nothing more than a not so educated guess.
Baby Boomers have played their progressive part, but they only came along post-WWII to about 1965. The racist Margaret Sanger, of Planned Parenthood fame, was a progressive from the early 20th Century.