In my opinion, unwritten rules are for gatekeeping. And if a new person follows all the unwritten rules, magically there's no one willing to review.
I think this is how large BFDL-style open source projects slowly become less and less relevant over the next few decades.
Fir these projects everything "tribal" has to be explicitly codified.
On a more general note: this is likely going to have a rather big impact on software in general - the "engineer to company can not afford to loose" is likely loosing their moat entirely.
For large works, the burden shifts, since you are increasing the maintenance load. Now we have the question of who will do the future work, and that requires judgement of the importance of the work and/or the author, and hence is a fundamentally political question.