Income isn't wealth. Someone making $62,000/yr in income without working at 55 (i.e. no Social Security) is likely comfortable. That's >$1m in invested assets plus whatever is owed to them as retirement income when they reach retirement age. It's especially unclear if everyone else's payroll taxes should be spent allowing this person to retire a few years earlier.
This is all before including the other large personal expense (housing) for this person is likely imputed rents from homeownership which aren't counted as income but function that way.
Surely you are capable of thinking there are tradeoffs here where one can set a level without dealing in absolutes. Put differently why not expand Medicaid to cover every American regardless of income? 400% is just as arbitrary as 1000000%.
I do actually think that universal healthcare is the best policy. But that will mean some wealthy people get coverage paid for by the state, which aggravates some people.
A substantial amount of discussion in early retirement communities is about how to stay below 400% AGI, which is why I found it odd to see a criticism of healthcare subsidies going to early retirees in the context of the expanded subsidies.
Great then you have even bigger problems to wrestle with regarding solvency. Americans won't choose cost effective treatments, and if you force them to pay out of pocket for experimental therapy you will be accused of running death panels. Good luck with that. On top of all that, they are also unhealthy due to a variety of lifestyle factors including that their primary mode of transportation likes maiming them.
This is all before including the other large personal expense (housing) for this person is likely imputed rents from homeownership which aren't counted as income but function that way.