If history is any indication, people wanting to make a lot of money will.
I like your idea better than most Craig, but who's gonna pay for it?
In a capitalistic society, big business would never allow the cost of all goods to decrease so much that money was no longer useful. it would be financial suicide, and who's going to invest in that?
A characteristic of businesses is that many of them will commit great resources toward short term profit. The computer microelectronics industry is a case in point. Early computer manufacturers didn’t plan to reduce the cost per transistor of computer chips to the extent that per-unit revenue was reduced from 1960s millions of US dollars to 2000s hundreds. They did it because they, and their competitors, could, resulting in short term gains in market share, but the eventual near collapse of profitability and exporting to other nations of an entire industry. As a result, electronic devices equivalent to ones costing more than a hundred dollars 30 years ago are in many cases now actually free.
In much in-depth speculation about post-scarcity – nearly all of which, in my experience, is in the domain of speculative fiction – the disappearance of present day economic system and instruments occurs not due to a peaceful or violent revolution, but because they can no longer win customers from their moneyless competition. We see something of this in such modern industries as software, where support service-based free software such as Linux operating systems and open-source applications are increasingly gaining market vs. their proprietary commercial competition. Although software, and to a lesser extent microelectronics, are an unusually dramatic example of reduction in cost and price, they show that such dramatic reductions are in principle possible.
In short, arguments, albeit very speculative ones, exist suggesting that the same psychological and sociological tendencies that invented money – tendencies including competition and greed – may also create conditions rendering it obsolete. I find this cause for optimism, because I think that changes in means of production, distribution, and trade are more likely than changes in psychological and sociological tendencies.