Blu-ray's the thing right now. A lot of studios are pushing hard so that people would switch from DVD to Blu-ray by putting the special features only on Blu-ray versions of their movies. Bond's not the only franchise that's doing this.
Mr Martin those days of 2 disc DVDs are over, it's all about Blu-ray now, heck even those with Blu-ray are getting shunned, Studios are putting many extras on the 3D Blu-ray versions but yeah no good special features until you upgrade.
I wonder if the studis will actually lose money this way if many won't switch to blu ray. I have only 2 things in my blu ray collection and I've had a blu ray player for 2 years, which I bought to hook up to my hi-fi as it stopped reading discs (thought it was a good excuse to buy one). I kind of hoped that there would be something interesting on blu ray. Problem is only have one blu ray player but multiple dvd players, which makes it easier if I want to watch it in a different room.
I have also noticed that the price of Skyfall was £10.00 when released but the other 2 (with 2 discs were only £7.00). Similar thing happened with Dark Knight Rises. I now don't bother much with pricey dvds with no frills and wait till they drop to about £3 (still haven't bought or watch Skyfall and I borrowed Dark Knight of a friend instead). I'm even buying second hand dvds for the first time from marketplace sellers like Zoverstocks where older films can be as cheap as 1p plus postage