I don't think the issue is the cost to the patient, but rather that in a private payer system, it becomes profitable to keep patients alive for as long as possi

I don't think the issue is the cost to the patient, but rather that in a private payer system, it becomes profitable to keep patients alive for as long as possible. In a public payment system, you could crassly say that keeping patients alive is a cost to the system. Now, that would seem to imply that the public option might lead to early termination of treatment in cases where treatment would be feasible but expensive, and perhaps that does happen.