Additionally, even if your definition of wealth is "Only things that keep you alive" isn't it impossible for you to deny that we are a "wealthier" society now then we were before the advent of modern medicine... as peoples lifespans are greatly extended.
Thereby proving wealth ISN'T a zerosum game. Since if wealth was a zerosum game that means there has been an equal amount of wealth through out the entire history of mankind?
http://en.wikipedia.org/wiki/Zero%E2%80%93sum_game