It's a bit more complicated than that. First, most large health plans regulated under the Affordable Care Act are actually subject to an 85% minimum medical loss ratio. Some of the larger payers which also have their own providers as employees within the same parent corporation are able to shift money around with internal pricing agreements so that they make larger profits on the care delivery side.

But at the same time, the business is still pretty competitive with the employers and consumers who purchase policies or rent networks being price sensitive. Employers will switch carriers to get a significant cost savings so that holds down prices (and carrier profits) to an extent. Most large employers (and unions) are now self-funded so the "insurance" company isn't actually bearing much risk, they just set up a provider network and process the claims.

Most doctors are almost completely ignorant about the broader issues of healthcare financing and medical economics so take anything you hear from your friends with a grain of salt. (And to be fair, it's not something we should expect them to be experts in.)