People who can pay the difference between the subsidy and the cost of Medicare will have Medicare coverage. Lower income older Americans who cannot pay the difference between the subsidy and the cost of Medicare will be covered by the Medicaid programs for the indigent.
Requiring a bigger premium share for higher income Americans would be fairly reasonable, but being unfair to wealthier Americans is not the first instinct of Congress members.
A quick review of the tax structure, or their proposed tax reform, primarily repealing the Alternate Minimum Tax, should confirm that. They actually mean what they say. Their problem is they don't have the votes to pass this abomination currently.
We've run out of other people's Social Security taxes needed to subsidize our low income tax rates.