That's because people like tangible improvements. Vista doesn't provide that across the board for everyone, especially for games currently.
It's similar to the 9x to XP move. A lot of gamers didn't want to go to XP because it most definitely was slower for a few years there. Vista isn't even as obvious of an improvement as XP was to 98.
By "tangible improvements" do you mean tangible things like benchmark frame-rate scores?...
That's what I'm getting from what you're saying. Truthfully, it wasn't that "XP was slower than 9x" at all--what happened at first was a learning curve as IHVs got their driver acts together, and game developers got their API acts together. Same thing happened when gaming moved from DOS to Win3.x, and then from Win3.x to Win95, and then from Win95 to XP, etc. No different at all in the move from XP to Vista. Lots of things have changed and it will take awhile for the dust to settle. But settle it will, you can rest assured...
I think that the improvements in Vista over XP are both tangible and obvious, but you have to be looking past current game benchmark scores to see them...
Let's be realistic about frame-rates for a moment, anyway. How much "tangible benefit" are we going to see in the future from frame rates steadily in excess of 60fps? I don't think many if any. Instead, the improvements will come as IQ per frame increases dramatically while the overall frame rate remains fluid and playable. Without changes to driver models and the APIs, correspondingly supported by IHV hardware support, we won't see these kinds of improvements, imo. Never forget that "new and improved" is what drives the market. The idea of "old and improved" is pretty much an oxymoron, isn't it? It seems to me that as Vista is the future and XP is clearly the past that embracing the future, instead of poking holes in it and complaining about it, is the only "tangible" way to go.