The American Medical Association owns copyright to all the codes and their descriptions. They have an extremely restrictive and expensive licensing options and they strictly forbid training models with the codes.
The AMA (a nonprofit!) clears ~$300M/year revenue from the codes, which is the direct cost passed through to consumers, but the indirect costs are the byzantine nightmare of OP.
This month, the practice was called out (https://www.help.senate.gov/rep/newsroom/press/chair-cassidy...) so the Overton window may be opening.
The AMA (a nonprofit!) clears ~$300M/year revenue from the codes, which is the direct cost passed through to consumers, but the indirect costs are the byzantine nightmare of OP.