Insurance is a very complicated business. Given you've listed negotiating rates with doctors as your first bullet, I imagine you should do some reading first on just how complicated the financial and regulatory side of the business is.

You can't just "charge more in premiums than you pay out". That is how insurance USED to work. Nowadays it's all about carry on people's money. If you are posting on hacker news about insurance I think you are in over your head :(