most 60s psychedelic biz actually isn't very psychedelic at all
with possible exception of Pink Floyd, tho their most far-out is ca Live at Pompeii, directly post-Syd but before they'd started curdling into arena space-rock
i.e. Blue Cheer, ne plus ultra of fuzz (what would be retroactively termed "heavy psych"), is way more de facto psychedelic than Love, or Strawberry Alarm Clock, or whatever
the break is as my dude correctly identified upthread, in mindset, world view, the possible
the actual sonics - both composition and technology wise - didn't catch up until about half a decade later
the real psychedelic late 60s stuff is is shambling chaotic drum circle stuff like Amon Duul I. it really varies in quality, but the attitude is right.
whereas most of what is labeled "psych" is garage rock, guitar pop, or whatever
I mention this cos it causes confusion when people are understandably like "but why isn't any of this, like, psychedelic"