as far as I know, they actually find a way to render DX 10/11 effect to be shown as much as good as it is with DX9 capability (they did it with Crysis warhead for consoles) which brings rages to enthusiast who spent thousand bucks just to make Crysis run almost flawless with max setup, and later find out their gear was to much overpowered to run warhead even with the max setup, okay this isn't my story, but I know someone who's definitely upset about it, and pretty much just stop caring about upgrades anymore and happy enough with his console purchased. He even said with consoles you don't have worried upgrading for at least 5 years and still happy with it, even if it less... it still lot cheaper.
Developer will try to do their best (most likely anything) to optimize their engine to run more smooth, better, faster, for consoles, with current technology on consoles they even releasing patch for some games.
but for PC, it's the user, you will have try anything starting optimizing your os, software, even worse upgrade your hardware eventough it isn't necessary, to run the games better, in the end... you'll still not satisfied because you know, it's not about the machine, it's about bad ports or bad coding.
Graphic does matter, no one think otherwise... but not every game with the most awesome graphics selling well, I dunno what's got in people mind nowadays but the purpose playing a game is to having fun, for example even people still enjoying playing tetris (and it's been remade in every way on every consoles/gadget/platform available in this world) and yet... you don't have to spend $5k worth computer to play it, that's not fun...for me at least.
if Tetris is a bit old-school for an example how about top world games best selling 2012? it's Diablo III, does it have the best Graphic out there? Yes, No? you decide, but at least it will run on any decent computer and ofcourse internet connection.