I think you need to think about society as something that can only "buffer" a few months of productivity, or a few years at most. It doesn't matter what monetar

I think you need to think about society as something that can only "buffer" a few months of productivity, or a few years at most. It doesn't matter what monetary system you use to value things. Prices will adjust to reflect supply and demand. It makes no sense for you to be able to save for X decades and then declare you have a right to Y decades worth of other people's productivity later in exchange. The only way to get what you want is to physically save the goods and services you want to buy in the future, but obviously that is impractical. Hence, society, markets, money, and inflation or deflation to balance the supply and demand of goods and services. Imagine a world where everyone is your age. You and everyone around you works and is productive. You're saving money. Then, you all retire around the same time. What value does that money have? You all have money, but there's nothing to buy with it. This is obviously an extreme example. But what you want is also extreme: that population and productivity are constant over time.