alt Hacker NewsThe original email RFC is also completely unaware of how bad spam is. Sure it might mention it but it's not really AWARE of the problem. The truth is, companies like Google, Microsoft and a few others have de-facto adjusted the minimum requirements for an email. Signing, anti-spam-agreements, etc.. are the true standard if you want an email to get from point a to b. (none of which are going to be REQUIRED in the RFC)
Given the amount of time that has passed, the big email companies have had many years to jointly update the RFC according to their experienced reality. They haven't done so and the way you describe how they effectively work together to adjust the minimum requirements (outside the RFC) is de-facto use of market power to the exclusion of other players.