prog wasn't the only stuff featuring these long jams and structures... a lot of it was at the dying day of the flower period...and the pop stuff, was... umm... what is a good word? fluffy... yeah "fluffy" works
you had Hendrix, and the Dead, and Zeppelin's first album, that has some booooring, long tracks on it, I love that album, but it took the psychadelic a bit far, by the end of 69 I'm sure a lot of people were sick of the peace, love, and happiness... someone wanted violence, destruction and blood
it wasn't only prog, it wass all the pop and rock music, it doesn't mean any of its bad or wrong, I'll go straight from listening to Ramones at CBGB's to Grateful Dead at Cornell U. I loved punk shit in middle school, I was a bit arrogant/ignorant in my ploy that all other music in some of my exact words.."f**king sucks d**k"
but there needs to be the love-y jams and the pure energy reckless horrifying punk rock, both kept each other in check