I do not think it will be the case this time. The biggest jump in rendering quality occurs when the entire shader pipeline went to floating-point with SM2.0 IMO which none of the previous-gen console hardware had. This gen, therefore it is different. Yes, PC games will look better, but I doubt it will look a generation better even four years after the debut of 360.
It wasn't features which drove superior PC graphics last generation and it won't be this generation. Its raw power. Features will of course be leveraged for extra effects but games will remain largely DX9 just as they were largely DX8 last gen (yes even Farcry, HL2, Doom 3 etc....).
However when you have multiple times the DX9 graphics pushing power plus a few extra DX10 enabled effects to throw on top, you a going to see some fairly healthy graphical improvements. What Rein is saying though is that the improvements could be so much greater if the games abandoned DX9 completely and made DX10 the minimum spec. But thats not going to happen until the next gen consoles lauch just as we didn't really see any DX9 only games until the current gen consoles launched.
We will see advantages of DX10 (and possibly DX11) on the PC but we won't feel its full impact until Xbox 3 and PS4. Thats just a sad fact but its no different than the previous console generation.
On the other hand I think all the calls of doom and gloom for the PC are greatly exagerated. I don't know if anyones noticed but cross platform development between consoles and PC has been soaring this gen. Thats probably due in large part to MS's efforts to make the 360 and PC as close as possible in development terms and the trend seems to be on the constant increase. Hell, there was even an announcement of a Dead or Alive game for the PC recently. PC exclusives may be diminishing, we will have to deal with that, but so are console exclusives. And as a result the PC platform is benefiting from a wider variety of games.
One thing is for sure, MS won't see the platform die as a gaming machine, its too valuable for their Windows stranglehold. Its always been my view that the xbox line was at least in part created to shield the PC from the ever growing dominance of the playstation in the gaming market. I can't imagine were PC gaming would be now if MS hadn't launched the xbox.