This one is for Doc. What happens when the demand side supplies itself? You have a commodity market.
What Doc usually means switching choice and the ability to build upon. But consider Sun's creation of a Computing Commodity Market. Buyers can sell excess capacity. This option, provided contracts allow (this is where the details matter), reduces the risk of buying too much in the spot market, and can increase liquidity. If Sun overprices the spot market, the buy side can sell instead of use. Volume will bring leverage in this market, but even the smallest buyers benefit from this option, even more than selling their extra servers on eBay.
Many will value different options and not take the risk of volatility -- but there is a risk management product that will be available for them -- the next opportunity.