They could be. I'd argue the real problem is competition. A person buys their car insurance. The purchaser is the customer, there are lots of competing companies, and prices are good as a result.

In health care typically your employer is the customer. The doctor and/or hospital also are customers. The insurance company is itself a customer.

Unlike - say - car repair you don't get a good estimate up front so it's hard to shop. Many times there aren't many good alternatives anyway. If you don't like a choice one of the actual customers made it doesn't matter because you have no real purchasing power anywhere in the system.