[prottog]

> simply holds a constant value in an inflation indexed manner

Gold and currencies backed by gold come very close to this, with historical evidence to back it up. The purchasing power of gold -- that is, its convertibility to goods and services you might wish to consume -- have remained remarkably stable over time.

Countries stopped issuing currencies backed by gold for a few different reasons, but its ability to hold constant value over time wasn't one of them.

[osigurdson]

Yes, true. Some economists suggest that the adherence to the gold standard prolonged the great depression. I suppose in some sense the entire economy is a kind of game where the goal (should be at least) to maximize the benefit to all participants. Having a stably valued token (fiat currency, crypto, gold backed, etc.) is a decision variable, not the objective function.