So what would happen under a fixed money supply? Well, a 5% GDP growth should be accompanied by a 5% decrease in prices, automatically. In other words, shifting prices would ensure market clearing. Now imagine an oil price shock. As an oil importer, you let your currency depreciate (no inflation targeting whatsoever, which would make your currency appreciate instead). So the oil shock is offset by your exports boom.
So with this fixed money supply and shifting prices, you can say bye bye to the inflation monster, as you don’t care about prices that change constantly. Now the question is how can people adapt to this? My solution is to drop cash altogether. Only debit cards and mobile phones and voice signatures. Then prices can become any fraction of any amount. With sustained GDP growth, a beer could become as cheap as 20 cents, while a phone call could be 0.0001 cent.
The Economist had already predicted the end of the cash era, but not the end of monetary policy.