It was only a matter of time before we started seeing Blu-ray exclusives... I'm just surprised it took this long.
It's not really exclusive. It's the same content as the DVDs (minus some special features); it's just been remastered. Aren't there lots of films that get remastered for Blu-ray that don't get a DVD re-issue?
(Granted, most remasters aren't quite so exhaustive and complicated as this!)