Earlier quoted context omitted.
I don't think the benefits of charging for your work are mysterious. It's reasonable to believe that certain works should not be behind paywalls, but not understanding is kind of a confusing stance.
There was a time when buying the Ansi C standard cost over $200 but you could get Herb Schildt’s “Annotated Ansi C Standard” for $20, which some said reflected the value he added to the process.
https://webstore.ansi.org/standards/iso/isoiec98992024?sourc...
Nobody does it. gcc/clang implement it from the "drafts", which are published online due to the need to discuss them prior to standardization.