Not sure how you fix it, maybe by temporarily making it illegal to allow a company to provide health benefits through insurers to fix this. Employers should only be allowed to give you the money for an individual plan (most startups sometimes do this instead). Employers don't pay your auto insurance, home insurance or other insurance. Maybe a one time convert of employer groups to individual groups managed for risk, then, for privacy, for business, for better health care the individual has that (also probably a back up plan for those in need).
Why should employers know about your health? This is ancient thinking where you stayed with a company forever. It's also a privacy thing. I think it would also combat ageism. It will also make starting companies and competing much easier with less friction. It would also allow employees to more easily go from job to job, when you have an employer plan it is a scary predicament sometimes.
Cost can only be competitive if they are seen, they will be seen if it is moved away from employer provided.