Yeah, not sure why this would happen, other than that it's a black mark on the record, and announcing it would be a pop of positivity for Xbox fans.
This isn't really PlatinumGames' forte, and it failed for that and a number of reasons the first time which haven't changed now. (However, did Kamiya work on that canceled Capcom game Dead Phoenix? He wasn't the director, but maybe he's always wanted to make a new flying action game?) And then, Xbox doesn't need this as a brand unless there's really something specific they're looking for. And it's not an inexpensive project, or a cheap developer to take a chance on (although Platinum seems to always be looking for work, so maybe they make good deals?) Also, dragon games don't seem to sell; Age of Ashes was good but apparently it's already dead and there's not been many other success stories with dragons in years.
Good luck, I guess, if it does come back?