We have a Constitution specifically outlining the powers of government, b/c the founders knew that the federal government would eventually try and accumulate all power unto itself. Flexibility comes at the state level, not the federal, unless Congress by 2/3 majority votes in a new amendment. That is the built in flexibility.
People are not responsible for their healthcare b/c they know government is out there with an open hand. There will always be a certain segment of any society that simply doesnt want to do what they should for themselves. You dont cater to that segment by enslaving the larger portion to the same mindset.
Medicaid, was set up to take care of the very problem we are talking about today. That was created 50 years ago. Safe to say that failed too. Which begs the question, why are people clamoring for the same entity to create another program, when it cant run the 2 or 3 it already legislated into law?