Each community could then form whatever organization they felt necessary to choose who to send to the triumvirate.
As as check on the power of the triumvirate, we could have something like a "Tribune of the Plebs" - a representative elected by open election from the entire community that holds veto authority over changes approved by the triumvirate.
Guido is not asking Python to live without a dictator. Guido is asking Python to learn how to live without Guido, so that Python may outlive him.
This is a tale as old as time. Apple lives on with only memories of Steve Jobs. The United States lives on with only memories George Washington.
For some inspiration I'd recommend listening to the track "One Last Time" from the Hamilton musical:
"One Last Time" - Hamilton At The White House #ObamaLegacy https://www.youtube.com/watch?v=uV4UpCq2azs
Original Broadway Cast Recording on YouTube https://www.youtube.com/watch?v=pEqnXNsAFL8
Original Broadway Cast Recording on Spotify https://open.spotify.com/track/0Iys022UwQ8xBfxE1g4nWZ
The UN Security Council is somewhat similar in that respect, though comprised of more members. New matters are approved by majority vote, but the five permanent members can veto anything that gets approved.
My proposal is somewhat tongue in cheek, hence the names from the Roman Republic - but I do think the idea is sound.
An alternate, simpler implementation would be to simply require that all changes be unanimous. I like the idea of a Tribune of the Plebs though because it gives a second means of a voice should a sizable minority of members of the sub-communities strongly disagree with the direction of their representatives.
The current governance model is mostly around consensus on the dev list. There's a "technical board" elected every release cycle from among the committers, to act as a tie-breaker when needed, and with veto power over DEPs (Django's equivalent of PEPs) and adding new committers. I don't know of a case where that veto power has ever been exercised, FWIW.
I could be wrong, and I don't follow Apple closely, but the impression I get from longtime Apple fans is that the last few years have been a stream of mild disappointments.