The COTS experiment

Since in the US rockets and spacecraft have all typically been built by industry anyway what NASA's COTS program really is is an experiment to see how small an organization can perform spaceflight and how cheaply, reliably/safely. (Clearly there are tradeoffs.  A cheap rocket may be possible but too unreliable/unsafe.)  Since most companies fail (go bankrupt and close) in 3 to 5 years and 90% of companies fail in 10 years this is a very real question and the answer is uncertain.  The two companies that are trying with Antares/Cygnus and Falcon 9/Dragon are currently well behind schedule. It will take some time and some number of flights to determine the reliabilty that results.  COTS is an engineering experiment.