The only ways to decrease the cost of health insurance are
1) make sure everyone pays in (individual mandate)
2) cut out the necessity for insurance companies - allow everyone to buy into Medicare at age-graded premiums
3) lower the actual cost of health care - I see the problems here, but don't know how it can be done
I'd split 3 into 3a/3b.
3a) reduce the cost of specific healthcare procedures/services
control prescription drug costs (no more Martin Shkrelis)
shift more work MDs currently do to NPs and PAs, more work NPs/PAs do to RNs, and so on.
shift more ER visits for non-immediately life threatening conditions to urgent care centers
require hospitals to publicize pricing so people can comparison shop for non-emergency care
3b) reduce the amount of healthcare procedures/services consumed
HSA style insurance (particularly with large employer contributions to the HSA accounts) tend to produce more optimized using of healthcare (people don't overconsume, but also see doctors when they need to).
Preventative medicine interventions to reduce the incidence of chronic long term illnesses, like diabetes, which is a lot cheaper to prevent than to treat.
End of life planning. Perhaps 1/10th of total healthcare spending in the united states occurs in the last six months of life and often is for interventions that prolong suffering or prolong life without consciousness. Many people would decline such interventions when they are healthy and lucid, but don't have a good advance directive in place for when they are no longer lucid.