The simple answer

Impact

The goverment run websites can not handle the pressure; the state run sites have tailor fit plans based on existing structures and are simply improving upon an unbroken wheel.  That leads me to believe there is a simple answer, one that most likely would be met with cries of infringement of sovereign rights of the states; re-write the law to say that to be in compliance with the law, states must set up their own markets.  Take the federal government right out of it in the long run and allow states to cover their citizens as they see fit, the only thing "big goverment" would be doing is saying you have to do it, but not how.