1. Government is less efficient than a privately owned, profit-seeking company--at least in most cases. If a business is inefficient, an efficient competitor will wipe them out. The same cause and effect doesn't exist for governments, except in the most extreme cases (revolution).

2. Markets that state and local governments dominate are large. Do you really think Waste Management would hesitate to take new markets that were previously controlled via government contract? Or that private prisons wouldn't purchase and run ones that were previously state-controlled? Or that power and water companies wouldn't realize the incredible opportunity to expand into new areas that were previously monopolized through government interference?