I think next-gen will easily be GTX580, probably stronger (I would say at least one generation stronger than a 580) with hopefully 2GB of video ram, and not come out until 2 years from now at the earliest. That's my guess.
And people are already making games with this level of detail, they just have to scale it back. All character models these days are built high res in Mudbox and Zbrush so the high poly count already exists. And if artists have access to SSS shaders for in-game, it won't take a lot more effort to use that. Some of today's games use SSS but it's really basic compared to what's being shown here.
I've said it before but I'll say it again, the tools have made it much easier to create content faster than 5 years ago. Motion Capture systems have come down in price, UVWing and texturing is easier than ever, modeling is faster than ever (even hard edge modeling) and shaders is all about what the engine is capable of. It doesn't take more artists. Most mid-level companies will use middle-ware engines like Unreal and those tools have improved so much to create AI, scripted events, set up physics etc. etc.
Budgets aren't going to skyrocket like they did last gen. They will go up slightly, but not insanely. If you go over to Zbrushcentral and do a search for Uncharted 2, you can see how high resolution the assets are that they created. We just need hardware to display it cleanly (IQ), with high resolution detail, better shaders (reflections, SSS and so on), much better lighting/shadows and more post processing abilities.