I agree with you that we have been eating through commodities like oil for centuries, but you can't possibly mean that these commodities are "savings"? Sure, the oil economy can't continue indefinitely, but neither can the universe (which, according to the second law of thermodynamics, tends toward entropy). I'm not trying to nit-pick but by savings, I mean not spending MONEY for a nontrivial amount of time. I'm all for trying to cut down on unnecessary consumption.
That's exactly what I mean. Money (and currency, not quite the same thing) is an abstraction of wealth, but not wealth itself. As noted by others, thinking of cash/gold as wealth is a common error. Think about what the "old money" of the North-Eastern US does. They certainly don't sit on billions of dollars, or even billions of dollars worth of gold; they buy assets and/or commodities. That's investing, but it's also savings. They may simply be buying equities in corporations, but that is still an abstraction of what real savings is. The corporate capital is the savings, and the stock certificate is simply a deed to a small part of that. The monetary price to aquire said stock certificate is only relevant to when it's bought or sold, the rest of the time it's irrelevent. In the novel Cryptocromicon, a wealthy character describes it like this, "Gold is not wealth, gold is the corpse of wealth; I can show you how to make wealth."
I don't disagree with any of the above, but (in this particular context), investing and saving are two entirely different things. If you look back through the thread, the user i was addressing was mistakenly assuming that his money should maintain its worth *without him investing it*. In other words, he felt that he should be able to put his money in his mattress, and come back to it being worth just as much as when he left it there. That's, if I am reading you right, the opposite of what you are saying. I have nothing against investing - we'd be living off nuts and berries if it wasn't for that.