It still seems to me that a bacronym is a kind of retronym. Similar concept, just applied to acronyms instead of phrases (or more usually adjective-noun combinations). I think bacronym will become accepted as a subset of retronym. No reason it shouldn't. In fact, it raises the interesting possibility that if the definition of retronym is expanded or broadened, that retronym may itself become retronymised. It could become a non-acronymic retronym. \:D