There certainly is the ability to do comparison shopping, as long as you have something routine and not emergency.
Some hospitals are better than others. perhaps you had complications at one vs another.
Insurance company apply standard pricing to all hospitals for the equivalent procedure. You can ask for reasonable and customary and they’ll most likely reduce the rate for you.
They are businesses and want to sell their service, again all you have to do is ask the hospital.
And now I don't have to ask the hospital. All I have to do is open the spreadsheet and do some comparison shopping on my own. One of the few things I've seen the government do lately that actually improves my life.