Bayonetta 2 was real. SEGA stopped giving a shit, like they did with a lot of things, including Max Anarchy. Bayonetta 2 was dead, and I have no reason to disbelieve the people who told me this.
It would appear, as others have stated, Nintendo went shopping for IPs. Bayonetta 2 probably had X% of production complete, and with SEGA disinterested in finishing it felt they could pick it up for an affordable price in order to expand their Wii U portfolio into an area they pretty evidentially lack in.
In addition to this, Nintendo is likely cultivating a relationship with Platinum Games. The company's two next games are exclusive to Nintendo platforms. They're published and funded by Nintendo. Nintendo obviously sees the talent and potential at the studio, and where the studio can expand the company's portfolio. Two games, especially these two, is a nice start. If they succeed, I can guarantee we'll see further collaboration. If they bomb, then Nintendo will probably look elsewhere.
And if they bomb, Nintendo's licensing of Bayonetta 2 may be limited, and I wouldn't totally rule out the possibility of a port to another system. But that's an if, and there are no guarantees.
As it stands, fact of the matter is if Nintendo didn't step in and pick up the Bayonetta 2 project nobody, nowhere would be getting it. Nobody wanted it. It was scrapped. Bayonetta 2 was dead. As a huge fan of the original, the way I look at it having the game is better than not, and I'm stoked Nintendo stepped in to salvage the project. It means I, a huge Bayonetta fan, get to play a sequel I otherwise would not.
Bitching about this collaboration that necessitates the entire game's existence seems so damn silly. We've all got our platform(s) of choice, but the simple fact of the matter is Bayonetta 2, as it was, was not going to appear anywhere else. If you don't like it, write SEGA some angry mail or something. Whining about it in a thread dedicated to the game's revival at the hands of an unlikely company is so petty and silly.