I did.
You want people to pay in installments after they get the treatment.
You are going to bankrupt the system, cause after people are treated, many are either incapable of working due to health reasons, or are dead. The bills never get paid after the fact, and the entire healthcare system would fall apart due to expenses being incurred and people not paying down their debts.
Your plan fails on a very basic economic level.
You are talking about a minority of people. Yes. Some segments of society, especially older folks, are more likely to die or become disabled because of a medical event. So, yes, in that case they will get free treatment. I think that has to be subsidized. Logically, it make sense to subsidize the older portions of society. For the rest of us, this will be like paying for a credit card. Except, with my plan, your payments are actually manageable because it is tied to your income.
People will pay. If they don't, they don't deserve care. If you're willing to pay for the ikea furniture you bought through your visa, you better make payments for your treatment...or next time, you won't get it.