You did not account for opportunity costs: each of those items were "worth" (futureofbitcoin) - to use your phraseology - the amount of time it would have taken Alice and Bob to acquire them after having starved and dehydrated respectively. However, neither Alice nor Bob forsook that quantity of time. So, the assurance of profit deprived each participant of what they "needed" and assured them only of what they already had in (at least, relative) excess.
Money extrapolates such deprivation to international markets.
An extremely convoluted argument is not necessarily a good argument.
"Neither Alice nor Bob forsook that quantity of time"
Which quantity of time? For what? Alice did in fact spend a whole 8 hours gathering drinking water, while Bob did in fact spend a whole 8 hours hunting for food. That time was spent.
What opportunity costs are you talking about? That Alice could have gathered drinking water for 4 hours, proceed to travel for 2 hours to the hunting grounds, and hunt for another 4 hours, to get what she needed?
Or that Bob could've hunted for 4 hours and proceed to travel 2 hours to the river, and spend another 4 hours gathering water in order to get what he needed?