Well, ask yourself this: do you think 640x480 is still an acceptable PC gaming resolution or do you see benefit in higher resolutions?

Of course games benefit from higher resolutions. Where you are incorrect is that 480p is not 640x480. It is 852x480. DVD's are the same quality, and they look pretty good. Sure, 720p, 1080i, etc are better, but not mind blowingly better. I'd rather see perfectly lifelike graphics at 480p than cartoony graphics at 1080p at this point. 1080p wastes a lot of processing power that could go into better effects and more lifelike images at 480p. Developers can't truly take advantage of the higher resolutions because of distance to the screen, and people who still play in 480i. Right now the real advantage is simply in texture resolution and jagged edge reduction.