Caveman--well, there's the freegans. They got the gathering down pat, anyways. But that's just a copout (on my part, not the freegans.)
And I think there's still a few survivalists out there. A while back I was poking around at the peak oil sites--and there really do seem to be people out there who relish the end of civilization, and a return to "nature" as a result. "A lot" of people wanting to return to paleolithic occupation as well as eating style may have been an exaggeration. And I don't think there's anything wrong with an individual wanting to live that way; It's just the idea that everyone should return to that state that I find banal. Just that it's not an option.
How many holes can you poke in it before the United Nations starts worrying about the cooling of the earth's core?
Boobycakes.