I don't think we should tax the wealthy into equality, I believe in income and wealth inequality -- its the incentive and reward structure an economy should have. However, it's only moral and right when coupled with a meaningful quality of life for the lowest end, and only when coupled with social mobility. Socialized medicine and the safety net allows for risk taking, allows the poor to build businesses without the fear of death in the event of failure.

Cost of care goes down when you stop wasting money on advertisement, CEO bonuses, and people whose job it is to deny claims. Cost of care goes down when you provide preventative care that's necessary and affordable. When you dont have people without insurance wandering into the ER at the last possible second who could have been treated for pennies on the dollar earlier on. All the data we have on Medicare backs this up, even though its an awful example for reasons I cited above.

Further if you claim that we can't afford to cover everyone, you're going to need to back up your claims because every other country in the OECD would disagree with you.

tl;dr: Income/wealth inequality is a good incentive, when the poor don't die, starve and can live well, and have the opportunity to move up. Socialized medicine enables this.