Why can’t insurance companies post the actual price they are paying and being charged by the hospital with proper billing taxonomies. They seem like they probably have these things well ironed out since they actually deal with various hospitals whereas hospitals only deal with themselves.
The health insurance companies are now required to publish this and in fact the rule went into effect July 1 2022.
Look up price transparency by CMS (the data will be published in this format: https://github.com/CMSgov/price-transparency-guide)
Note: the data being published by payors in machine readable format (MRF) is MASSIVE - terrabytes of data. Example: https://transparency-in-coverage.uhc.com/