By the way, there has never been anything stopping the states from creating their own single-payer systems.
Technically thats true, but there were numerous obstacles in the way of doing so before the ACA.
For one thing, in the old system, a single state with universal health care would be a magnet for the sick poor. This would probably destroy the system.
Under the ACA, the poor are essentially entitled to coverage no matter where they live. A single payer state may still be attractive in terms of lower insurance cost, which really only affects those who are paying for the premiums themselves.
My understanding is also that there are some technical legal issues with the new Medicaid rules which make this much easier now which has caused some states to look at it. All we need is a couple of them to get the ball rolling and they could even form inter-state/regional pools.
BUT if objects for gratitude and admiration are our desire, do they not present themselves every hour to our eyes? Do we not see a fair creation prepared to receive us the instant we are born --a world furnished to our hands, that cost us nothing? Is it we that light up the sun; that pour down the rain; and fill the earth with abundance? Whether we sleep or wake, the vast machinery of the universe still goes on. Are these things, and the blessings they indicate in future, nothing to, us? Can our gross feelings be excited by no other subjects than tragedy and suicide? Or is the gloomy pride of man become so intolerable, that nothing can flatter it but a sacrifice of the Creator? --Thomas Paine