Maybe the law can be changed to incorporate a "wealth" test instead of the current MAGI test; then I think the costs might become more bearable to the public (i.e., taxpayers) and the system (i.e., exchanges) can stay.
A wealth test may not pass constitutional muster.
Today's ACA is based on the Premium Tax Credit and the Shared Responsibility Payment (now $0), both of which are based on income.
The Constitution prohibits federal direct taxes that are not apportioned by population, except for the income tax which is specifically permitted by the Sixteenth Amendment.
So legal scholars are debating whether taxes based on wealth would be constitutional. There were a flurry of articles about this recently when Senator Warren proposed wealth taxes.