vonHayek

The short answer is, they didn't. For a better understanding as to the why I suggest a reading of "Gresham's law." (warning: wiki link because it's late and I'm lazy) This is more popularly referred to as "Bad money drives out good." Though this is, at best, an overly simplistic representation of Gresham's thesis. I strongly suggest reading beyond my lazy wiki link if the subject interests you. Cheers! Curtis