Almost everything decreases in value over time, such is the nature of progress. I can have tens of GFLOPS available to me for a couple hundred dollars, in 1984 I would have paid $15M per GFLOPS. That's a decrease of value of over 99.999%, in only a quarter century. Someday gold will be cheap, too, either because the bubble bursts or some researcher makes a gold machine. I don't have a right to value.

Cash has always been a relatively poor investment, useful only because its convenience and liquidity are second to none. Inflation serves both of these purposes. If you don't want to use dollars, you CAN invest in stocks, gold, or just get chickens for bartering.