Does that also factor into account that manufacturing has largely been moved to other countries? That is, does the average US consumer spend fewer resources than in 1960, taking imports into account?
Oh, and forests are growing back some places too, though I don't know about the US on that one. (That's why technological advances are good - it's harder to get clean energy than is it to burn wood for warmth, but it's worth it once you have it.)
I'd guess resource usage has grown a LOT