After studying this topic intensely for my own sake, I'd say it is more common than you thought because childhood trauma is more common than you think.
It can even be minor, little things that can cause memory splits in children for survival sake. These splits set the ground for future splits.
I think it can be very strange that the people who are not broken stand out as weird (and maybe even aloof) in a very broken emotional society.
As I've been healing more and growing as a person, my extended and close family, which unfortunately are extremely dysfunctional, have pushed me away more and more. It seems like most people have a story like that, which is why I do have hopes that journeywork and related spiritualism, or at least some kind of vehicle, social or otherwise, with that kind of strong effect comes forward in the coming years.
Thanks for putting the book down too, now I'm really interested to read it. :D :))))