What makes a "true believer" better suited to start a religion, his delusions? Actually I think most religions started exactly that way, some guy found a way to use preexisting superstitions and used them for his benefit.
In the case of the three monotheistic religions this is factually wrong. At least during the emergence all of these religions were concerned with social and not personal stuff.
Just read some random parts of the bible, the myths of the ancient Israelites are concerned with regulating social life. God becomes the absolute, the law or however you wanna call it. In the Gospels, or rather mainly in the Pauline interpretation of them, the main idea is to create a society which transcends the boundaries of Judaism and in Islam there is the same idea, end the rivalry among Arab tribes and unite them.
Of course during actual religious practice these ideas soon vanished. Ironically the very universality of Christianity and Islam caused this as it led to a rapid increase of believers which led to a power structures and an abuse of this power. Judaism is a tribal religion and lacks these universal ideas yet precisely because of this it never became strong enough in numbers to do the nasty shit the folks of its two descendant religions have done.
Well, that's all a lot of speculation about the motives of ancient people obviously as opposed to Scientology where we have documented proof of what Hubbard said in the 50s.
What some judge to be delusions now were just a natural part of life in ancient times, and used to explain what was then inexplicable. Taking people to task for things they were ignorant of due to the limitations of scientific understanding in their time doesn't make much sense, and certainly doesn't compare to the actions of a man thousands of years later who knew better.
Sure, they could have used preexisting ancient beliefs for their benefit and most definitely did it to exert influence (for selfish or benevolent reasons or possibly both), but my point was that at the beginning they probably believed the supernatural prophecies and events they were describing were at least real or possible, whereas Hubbard was fully aware his stuff was a completely fabricated scifi story created solely for the purpose of personal gain. That makes a difference to me in terms of granting a religion legitimacy as an institution (though it doesn't make me any more likely to believe in their dogma).
There is a wonderful book called "Did the Greeks Believe in Their Myths?". One of its main conclusions is that the ancient Greeks did not believe that all the mythical creatures still roam the Earth but that they once did or that their ancestors believed in that kind of stuff.
"I believe" is a modern notion, it has been far more usual during human history to not believe subjectively but socially or via a third person.
My grandmother regular went to the church but when she died she did not really expect an afterlife. Belief for her was more of a social thing. When I was still a Christian I never really believed in an afterlife either, at least subconsciously I was always aware that this is just a story which we tell ourselves to endure mortality.
Or take Santa Claus. you wanna give some sweets to the kids and do not believe in him and at a certain age the kids realize that he ain't for real but still pretend to believe in order to satisfy their parents and get the sweets. So nobody subjectively believes in Santa Claus but the game still runs.
