I guess my main problem with this hypothesis is that it assumes there is one 'real' personality and all others are 'alternate' states. I would argue that there isn't one 'real' or 'one original' personality at all. Going back to your analogy of a toddler's mind that was broken before it had the chance to form... there was never one entire personality at all. there was a collection of self states which were all 'normal' but simply never had the chance to integrate.