How would lowering the Medicare age save the system money?

[democrattotheend]

4. The current premiums for Part B are heavily subsidized

If people under 65 were allowed to buy in for the premiums currently charged to Medicare beneficiaries, it would cost the system a lot of money, because the premiums for Part B that current beneficiaries pay do not nearly cover the cost of providing the benefits.

If the buy-in were not subsidized for those ages 55-64, the cost would be over $600 per month. Would people ages 55-64 who don't frequently use medical services opt to pay that much when there are cheaper plans out there with higher deductibles and copays? Other than a few people who might choose Medicare over a private plan for ideological reasons, I can't see too many healthy people opting to subsidize Medicare by buying in when there are more affordable options.

I know that COBRA, while designed not to cost employers much other than administrative costs, has ended up costing employers more than expected because of adverse selection. If the employer had a decent healthcare plan, premiums for COBRA can be very expensive, way more than any healthy individual who uses medical services infrequently would opt to pay. Thus, COBRA has made the employer's risk pool sicker on average because only those who need frequent medical attention opt into it.

Of course, there is always the option to subsidize Medicare buy-in, but then that would cost the system money rather than saving money.