Why is 70s psych almost completely ignored?

So many people say that psychedelic music came crumbling down once 1970 hit, but why? The 1970s had some phenomenal psychedelic music, it's just heavier than what was being made in the 1960s. You also had progressive rock really starting to get big, and you can argue that prog is just a natural progression of the sound

Europe, Mexico, South America, Africa, Japan, and even India had phenomenal psychedelic scenes in the 70s