Technically, the problem in the 'capitalist' (for lack of a better word) economy is that all of the variables that make up the economy are interdependent: each influences and is influenced by all other variables. That is the definition of a chaotic system.

With my proposal, one variable--money (as currency)--would be independent of any and all other variables in the economy. The amount of it would be determined by demographics. It could not be influenced by anything happening within the economy. That variable would thereby govern the economy (total output and price level), passively but effectively.