Perhaps so. Throwing comments into the mix to shake things up a little.sorry, but i think the premise of this gives Hubbard and Scientology too much credit.
It was an interesting period.They were but one point in the counter-culture milieu of the 50s-70s, and specifically the human potential movement, a complex morass of influences and cross-connections that form a web like one of those crazy charts that conspiracy theorists create.
though Hubbard had a knack both for garnering inordinate attention and publicity, and in posing himself as the 'source' of everything even though he heavily plagiarized earlier sources and took credit for the work of those around him. it seems to me that ex-members are people who bought into that at the time, reinforced by policies like those against 'other practices' that might have caused them to start to find out how un-original the concepts and practices really were, and who sometimes are still partly under the thrall of the illusion.
Scientology itself could be said to be an offshoot of Aleister Crowley's work (Thelema) -- and some new religion scholars peg it as just that, alongside Anton LaVey's CofS (Church of Satan). that might seem like an inadequate way to portray it -- but so is positioning Scientology as the source of anything remotely similar that happened after the early 50s.
lots of people did Dianetics and Scientology, which were kind of the 'in' thing to check out for a while, and other things as well before and after, and then went on to do their own thing. like, i've seen accounts that a lot of people at the time had read Zen and the Art of Motorcycle maintenance, Siddhartha, and other period classics before getting into Scientology, and even joining partly inspired by those works. as i see it, it's a chicken-and-egg problem in at least 3 dimensions, not easily simplified.