Sometimes studies just tell you what is already obvious. Health insurance premiums are high and growing rapidly. Guess what, far and away the single biggest component of those premiums is the cost of actual health care, the prices for which are increasing faster than insurance premiums. A relatively small component is administration and profit. A study from Yale confirms this obvious fact. It finds that from 2011 to 2024, health insurance premiums rose by 78.4% while the cost of delivering health care under those plans rose by 84.2%. Administrative costs and profits declined. Health care costs accounted for 91% of the growth in health insurance premiums. Health plans could probably find more ways to be administratively efficient, but the focus needs to be on reducing the prices of health care services and goods, and on reducing inappropriate utilization. Without that, we can expect to continue to see very large health insurance premium rises. And of course the politicians are making this worse by eliminating tools, like prior authorization, that health plans use to control health spending. (JAMA Study)

over utilization is one of many factors –
An example is my personal situation
I have a heart issue that is very unique but almost exclusively found only in endurance athletes which is a 700+ calcium score. Anything over 400 is indicative of a 100% chance of cardiac event within 5 years in the general population, yet less than a 10% probability over the next 25 years in the subset of population which are endurance athletes.
I went 10 to 12 tests exploring the issue racking up $50,000+ in medical costs (all paid via insurance). The cardiologist prescribed the excess tests because they got paid for the tests. I switched to a different cardiologist who had a better understanding of the uniqueness in the subset of the population of endurance athletes.