I think frankly we (including LaBerge) don't really know exactly how/why MILD works. LaBerge's insight that he wanted to remember to do something in the future (while dreaming) was (IMHO) just the mental "schema" that he used to describe what he wanted to do. My opinion is that MILD is just another framework within which to mix up the soup of self-awareness, expectation, intent, and memory, which leads to lucidity. "remembering to do something [realize you're dreaming] the next time you're dreaming" just seems too complicated to me, ala occam's razor. Even prospective memory may be a red herring, since it seems to me to be a sort of all-day mindfulness / active goal center thing.