Whenever I see mentioning of hitting the graphics wall, I get the urge to post the following:
And yes, this is all computer generated, off-line off course. Once we get there in real-time, we might be able to talk about that wall. Not to mention all other things, like physics and AI, you need power for (both CPU and GPU).
As for game budgets - yes, they are rising, so is the market. If you look at Hollywood action flicks, their budget is steadily rising, but that doesn't stops them making new ones. I can only see similar thing happening with games.