You may be shocked to know that health insurers are not in the business of paying for healthcare. Rather they are in the business of making money and refer to payments for healthcare as "medical losses."

Premiums on a policy are not locked in and will be raised as to cover the insurer’s expected medical losses plus another 25-to-50 percent for administration and profit. The insurer decides what losses to expect on a given policy based on the application (age(s), life situation(s), and possibly medical background(s) of those to be insured) plus the history of medical losses on that policy. A policy can be recinded (retroactively cancelled) for any errors or omissions on the application — all insurers have rescission departments dedicated to finding reasons to retroactively cancel policies that lose a significan amount of money. Also, Americans covered under group policies will lose their coverage whenver they drop out of or are dropped from their group, e.g., if they become too ill to continue at their job. James Kwak has much more about this here.

The problem is that most Americans interviewed claim to be satisfied their health insurance. But that’s only because most have not yet experienced an expensive and lingering illness.