Your theory is great, but “seniors” have been led to believe by our government that Medicare would be there for them. Most don’t have the resources to purchase the type of insurance you mention. Now consider that your typical 50 year old has paid into this fraud for 30 yrs already so he/she’s unlikely to start diverting significant funds to private insurance.
So the logical result is rationing and death panels.
If we were not supporting a massive underclass with illegals to boot, it would be there. But now, Medicare is subsidizing the women who breed like rabbits, illegals who come and breed like rabbits, and teenagers who are having one kid after another. And their children do the same thing, one generation after another. That’s were the liabilities are coming from. THAT is the root cause the social security benefits are such a mess and bankrupt. We have to start with a lot of tough love and simply start cutting people off who haven’t been paying in. It has to end because if not, either a lot of people are going to have to train as physicians to get the help they need, or people will have to live with rationed health care. A disaster in the making.