I don't think people purchase a console because of the graphics. I think they purchase the console because they want it (for whatever reason) and then use the graphics to justify that purchase to others. That's not everyone of course, but I think it's a lot.
Most visual "nutters" had no problem owning the weakest system last gen with the ps2, or really any generation before that. In fact it seems most of them don't even realize they had the weakest system last gen.