Better off in what regard? In feeling? For when an item is traded, 1 party loses the traded item, while the other party gains. So comparative advantage is in perception. The actual phisical stuff is lost or gained, therefore it is zero sum. It matters not that you value ur oil less than the guy that is willing to pay for it with dollars. How many a people have been sorry for the decisions of their predecisors. The russian tsar sold Alaska, for he thought what use he has for some extra tundra when he has so much of it already. But then the following generations condemned that action. On the one hand comparative advantage would state: "The tsar gained dollars for what was marginally less valuable to him, therefore both sides gained" But that overlooks the fact that controll of that material posession was still lost. Furthermore consiquent developments have shown that Alaska was sold dirt cheap too.

In any case, value of traded items stem from our current needs. Our current needs are temporal, therefore value we attach to our posessions are temporal and are subject to change. State of our current needs does not negate the fact that a bottle of watter is a bottle of water and will be gone if we traded it for something else. Comparative advantage argument has merit, but one that does not apply here.