The true progression of gaming has gone from the original Ultima for the PC on 10 5.25 discs to gaming posisbilities using the space available on a high definition disc. Notice here I did not say which HD disc.
The bottom line is that when programmers are given anything they are going to use it -- wheather that is memory, CPU speed, cache, Graphic GPU's , graphic memory , hard drive space, intial storage space on a CD, DVD or high def disc.
The programmers will use whatever is available to them. So lets see, a DVD-9 can hold what -- 9gb ? and a BluRay can hold 25 GB. So that would be 3 DVD's to one BluRay. Gets interesting when we double BluRay to 50 gb as that would be 9 DVD's. So I can see how that would get most gamers dander up if one said (like I believe Sony has) that in order to do true HD gaming you would really need a High Def delivery system like BluRay.
But can this possible be right? If we look at the CD to DVD transistion you would see 470mb to 9gb! So we would be talking 18 discs to one DVD-9! Well it did not take long for the programmers to blow right by the CD limit. Why can no one here see that in a year or two some programmers will blow right by the DVD-9 limit? It is going to happen sooner or latter. The game will have better graphics, textures, aninmation, sound, play mechanics, high resolutions, less repetition that are being seen in too many games right now.
Just because M$ says that you don't need it does not neccessarily make that the truth. Just because Sony says you need it right now does not neccessarily make it the truth.
But if history is telling us anything, games will get bigger, longer and better looking and that is going to use more disc space for delivery. That is just the nature of gaming -- whether it happens now or latter is moot. It will happen and right now the PS3 is designed for longer use then the XBOX360 in this current gamming generation. Whether that pans out will depend on the programmers and the people who buy their games -- the customer.