I can tell you exactly when I bought Ummagumma. It was Friday 31 Aug 1973, between 12:30 and 14:00. "...Oh yes, after lunch, I popped into a record shop in Carnaby Street and bought Ummagumma by Pink Floyd. It sounds a bit dated on first hearing but it's probably the kind of L.P. you have to play a few times before getting into...'
Then on Monday, 3 Sept 1973, evening, "...Then for the rest of the evening I got into Ummagumma. There is some really heavy classical piano stuff in it. I can see now why it sold so well. It's brilliant...."
So the music is fine. I bought Relics at some point, which I adored plus Syd Barrett's Opel and Madcap Laughs. I recall I once had a scruffy secondhand LP of Dark Side of the Moon, which I don't recall playing much at all and soon got rid.
It's not that the music was bad or anything. Elsewhere, I have a few lines of Granchester Meadows jotted down...a song by...Roger Waters.