$749 million is revenue. Revenue less expenses (i.e. profit) was $57 million, which admittedly is a decent 7.5%. But as a nonprofit there are no shareholders or partners to siphon off that profit. The common argument is that management siphons off that money through salaries, and I can't say they don't, but if you look at their assets & liabilities it seems like some significant amount of their profit is going into savings.

Anyhow, the Blue Cross/Blue Shield system has a very complex structure so if you're looking to find where the real money is being siphoned off it's unlikely to be at the top. BC/BS affiliates are independent, that's why the org at the top for a system insuring over a hundred million people pulls in less than a billion dollars in revenue.

"Nonprofit", at least in the US, is usually shorthand for having received a 501c3 (or similar) designation from the IRS. It has little bearing on your ability to make money as an organization (with caveats like the public support calculations)

Source: Ran a nonprofit for a few years that made money doing software consulting