Hospitals and doctors do this on purpose. They charge ridiculously high rates so they can always get the absolute maximum from any given insurance company. They have to charge an initial rate higher than any insurance will possibly pay so they can max-out their profit.

If you happen to not have insurance, well they bill the same stupid-high rate and you have no negotiation power like an insurance company does.

I've seen this myself. Just walking in to an ER can be $5k even when they don't do anything at all. God help you if you actually need care like an x-ray, CT/MRI, bandages, overnight+ stay. I had a CT done for broken ribs and it was $15k for the scan all by itself, plus the $5k ER "facilities" charge, plus all the various doctors each had their own charge (about $2k for each doctor). Healthcare in the US is totally borked.

Most people don't really understand how bad it is because they've never been without corporate insurance (maybe self-employed or other reasons).