The only benefit of health insurance purchased via employers is that you can use pre-tax income to pay for it. Otherwise, it has all the same deductibles and out of pocket maximums as policies purchased on healthcare.gov, except for government employees and some unionized businesses.
The answer is that most Americans still have pretty decent lives, and they like those in power (whether or not they are actually benefiting).
Not necessarily. The risk profile of the group in a specific self insured business is not guaranteed to be healthier than one not part of a business.
Most states publish their approved premiums for healthcare.gov plans, and I don’t think I’ve encountered a self insured business plan with materially different premiums/deductibles/oop max.