BFD - the law allows for the federal government to set up the exchanges and eventually all states will get on board (most likely sooner rather than later)
I'm pretty sure the feds pay close to 100% of the states costs for the first few year and upwards of 90% + after that
the Repubs governors will quickly realize (and I'm sure they already know it) that in the long run this will save them on health care costs. Those future health problems aren't going away so if people don't get insurance coverage they will just get emergency treatment or access to coverage that eventually costs the state money
and of course, the political pressure to get on board will grow too