That makes absolutely no sense. If it's all about the money, and hundreds of thousands of people want Vanilla and making Vanilla servers is simple, easy and straightforward, logic says they would just go the easy way and just open those servers and make money off those hundreds of thousands of people, no?
Again, while I do support the idea of Legacy servers, and I do believe it can be done in a way where it becomes self-sustainable and doesn't harm the current game, it's just not that simple. You're doing more harm than good to the pro-legacy argument.
Blizzard might be greedy, and be in a lower place than it used to when it comes to their gameplay-first and gamers-first ideology, but it's far from an evil entity feeding on our hopes and dreams like some people paint it.