Stevenson was a genius, the truth about reincarnation has long been suppressed by many of the popular religions who need a constant supply of cannon fodder for thier various wars against other popular religions that beleive in exactly the same things as they do.
Think about it, what is the point in fighting and dying if you are going to come back as a toad? Paradise sounds better to the common mans mind.
Of course, some religions are more enlightened. Ever heard of a Buddhist invasion force, for example?
Reincarnation was probably never intended to be viewed as people see it today, but rather, as a metophorical vehicle for the concept of Karma.
Karma is indusputible for most people and it appeals at a very low level in our minds, right down there with fear of fire and the need to own a large TV.