The real problem with Vista and resource use came from the OEMs. Details here:
http://blog.seattlepi.com/microsoft/2008/02/27/full-text-mic...Microsoft has a program where they certify that hardware will work acceptably with their operating systems. This is important in the run-up to a new version of Windows, because during the period when everyone knows that Windows X+1 is coming soon but all you can buy off the shelf are machines with Windows X, people want to be confident that they'll be able to upgrade to Windows X+1 when it's available.
For Vista, if your machine passed this certification, you got the right to ship it with a shiny sticker that said "Vista Ready." Seeing the "Vista Ready" sticker on that XP laptop on the shelf at Best Buy told customers that they could buy it without fear. It was certified future-proof.
However, Vista required more resources than XP did to run with acceptable performance. That meant that OEMs had a ton of ultra-cheap XP machines in the pipeline that could not with a straight face be called "Vista Ready." And this was a problem, because they didn't want to get stuck with warehouses full of machines nobody would buy because they couldn't run Vista.
So what they pushed for, and what MS eventually gave them, was a new certification: "Vista Capable." Unlike "Vista Ready," "Vista Capable" didn't mean Vista would run well on the hardware in question. It just meant you could install Vista on it, with no guarantees as to how it would actually run. And the shiny "Vista Capable" sticker looked pretty much exactly like the shiny "Vista Ready" sticker, so if you weren't looking carefully, it was easy to confuse the two.
The OEMs loved this solution, because they could now slap "Vista Capable" stickers on all those crappy XP machines and unload them on people. But, entirely predictably, then Vista came out and suddenly tons of people were installing it on hardware that was nowhere near beefy enough for it. So for umpty-ump millions of people who bought that crappy hardware, the experience of using Vista was painful and awkward and slooooow. Eventually even the cheapest machines were powerful enough to meet Vista's requirements -- but by that point Vista's reputation had been sealed. As the saying goes, you never get a second chance to make a first impression.
But the OEMs did get all that inventory out of their warehouses. So, you know, mission accomplished.