Who can tell what goes on in the deep, dark spawning pits of Game Freak? The only way to know for sure is to ask the man (or woman) who was in charge of creating the move Vacuum Wave and the woman (or man) who was in charge of Gen IV Move Tutors. It may make a return someday, but for now the mystery of Vacuum Wave must remain unsolved.
TL;DR Game Freak, and Game Freak only, knows the answer to your question.
