Hi,
@nad wrote:
I wrote a draft PEP to formalize the process to become a core dev: RFC: Process to become a core developer.
I also wrote a process as part of my PEP 8015:
Promote a contributor as core developer
Once an existing core developer considers that a contributor is ready to join the core group, to become a core developer, that core developer asks the contributor if they would like to become a core developer. If the contributor is interested in such new responsibilities, a vote is organized.
The vote is reserved to core developers, is public, and is open for 1 week. Usually the core developer who proposes the promotion has to describe the work and skills of the candidate in the description of the vote. A contributor is only promoted if two thirds (>= 2/3) of votes approve (“+1”) the promotion. Only “+1” and “-1” votes are accounted; other votes (ex: null, “-0”, “+0.5”) are ignored.
If the candidate is promoted, usually they get a mentor for 1 month to help them to handle new responsibilities.
If the candidate is not promoted, a new vote can be organized later, when the candidate gets the missing skills, for example 6 months later.
I agree with @nad that it would be nice to better formalize the process. The PEP 13 is quite vague on that part: PEP 13 – Python Language Governance | peps.python.org
My point is just that sometimes it can take a very long time. Sometimes we “forget” to promote valuable contributors 
But it must not be only required “skill”
I’m not saying that it happened in the past. But I’m not sure that in the past, the promotions were always “fair”.