Who's making that conclusion? As far as I can tell, nobody's attributing his success entirely to LSD. I'm sure he'd have been successful without it. But a person is a product of their experiences, and he plainly states that LSD factored strongly into it. You can disbelieve him, but I don't know why one would have trouble believing that.
I tend to agree that this is only getting so much play right now because of the Jobs connection, which is getting annoying for some, but that doesn't make the points being made any less valid.