[conanbatt]

This is a common criticism but I don't think it checks out:

Medicare is funded by payroll taxes. So it already works as in "the young pay for the old". Its true insurances have incentives not to have diseases before patients to go medicare (for example, if they knew something has high risks at old age, but low risks before, they have an incentive to do that). Working in the industry I have yet to see an example of this, so I think its a greatly exaggerated claim.

OTOH, hospitals are forced to take medicare patients, and the reimbursement rate is up to half of what regular insurance pays. It is often below cost of care. This implies a cross-subsidy from private to medicare.

I think the final math on this topic is ambiguous. I would not make a claim either way without some stronger analysis.