A thin philosophy like liberalism cannot build a society from scratch. It assumes too much, promises even more, and delivers it all too slowly, if at all.
How a system functions has more to do with how its governed than with the policy ideas in play. Implementation failure, constraints, and incentives all fall under the larger umbrella of governance.
Our health care is failing to improve because each invested player inside our system holds de facto veto power over those outside who try to change it.
A prudential approach will never deliver the rallying cries and exciting headlines (some) politicians need, but it always offers the best performance.
Medicare does not struggle for lack of ideas or funding. It struggles from funding thrown at the same tired ideas rooted in similar political traditions.