It kind of goes hand and hand. If the hardware makers are designing faster products, MS might as well make an OS that utilizes this speed. Vista core to speed is 'super fetch'. Vista is power hungry but if you feed it, it runs great. Even the game developers are utilizing this new found power and speed. We are seeing games that require dual cores and super lighting video cards. Rise of Flight for example. But, people like you and me will lay down the money for fast hardware because it is what we like to do with our spare time. We are just two of billions who do this as a hobby, etc. I can not be proof positive but Windows 7 will be just as hungry for power but, no matter, in a week you will have a fast computer that will take all comers with ease
PS: Yes, I held onto Windows 98 until my hands could not clutch it anymore. I lived through XP.