When I first read that, it seemed slightly odd that he would place so much trust (provisionally?) in this particular psychological explanation. Later I read The Jung Cult, which includes a persuasive argument against the validity of the evidence for a collective unconscious. (And I guess the author had to fill the rest of the book somehow.) You'll have to decide if you think the prior probability suffices.

Mind you, I doubt this argument would make all the phenomena go away.