Your 100% vs 25% is for completely different metrics. Insurers will pay out over 100% of premiums for some small percentage of people, but will pay out less th

Your 100% vs 25% is for completely different metrics. Insurers will pay out over 100% of premiums for some small percentage of people, but will pay out less than 100% of what they take in premiums overall, or else they go out of business. Insurers seem to make enough money to pay a huge staff and process a lot of paperwork, but you also have to consider the higher costs of health care due to the health providers also needing more staff to do "coding" (looking up codes which precisely classify medical services administered, there are many thousands) and other paperwork (and IT systems etc) needed to get paid by insurance companies.