So in that line of thinking, Hades, we would never see Star Wars games or books because that name is reserved solely for movies.
Might and Magic is just a fantasy world. Sure, it started off as a certain type of game, but it was expanded with Heroes of Might and Magic and now it's growing further with Dark Messiah (We won't talk about Crusaders.) It's a universe that developers are using to set their game in. Sure, it's not developed as thoroughly as D&D or Star Wars, but it's still an already created universe.
Growth is the key here. Might and Magic was dead. So was Fallout. These new games aren't interfering with the old style of games.