I mean, not to get cavey, but I am convinced that the insurance companies are at least 50% of the problem, and part of it is the employer provided part of it. Companies, for good reason, generally care more about paying the least they can for the insurance they provide (so, other than it being a recruiting tool, and making it attractive via certain inclusions, etc., they want it to cost as little as possible). They, then pressure the insurance company to keep costs down, which the insurance companies do by any means they can, which means they sometimes act like jackwagons. But, because that keeps costs down, they don't lose 'customers' (the companies who pay the bills). If your auto insurance, or life insurance, or whatever insurance that you purchase and pay for, treated you like your health insurance company...you'd dump them and get someone else.
Now, that's not advocating a specific solution, because there's a lot more moving parts to it...sure we could dump the companies that act like jackwagons, and go with another company, but short term, that wouldn't make everything cost less...much the opposite...but IDK, over time, I think it would come to a healthier place than the dysfunctional mess we have now with some other solutions.