Markets are often seen as the best way to schedule tasks in computer systems, but this belief may not be accurate. The theory behind markets doesn't always work well in real economies, including those for computing resources. The idea that markets are always efficient and don't need a central controller is not always true. In fact, there may not be a market-based system that can make everyone happy while being fair to all users. This means that markets may not be the best way to schedule tasks in a fair and efficient manner.