Maybe Wikipedia don't scale as gwern assumes.

You would think that editing work related to the number of pages is sublinear or linear, but maybe that's not true.

When the organization grows in numbers number of management positions grows logarithmically, but the amount of communication may grow much faster. Wikipedia has a editing hierarchy and process that is much more complicated than just a simple tree hierarchy for a good reason.

The culture of the organization may also put limits to the growth and is related to communication. You can't just assume that the organizational culture can be maintained without increasing efforts to maintain it. Large companies and organizations always struggle with this. The mission is lost.

I really hope that genuinely meritocratic pedias like http://www.scholarpedia.org/ , https://plato.stanford.edu/, https://www.iep.utm.edu/ will continue to grow as alternative to Wikipedia.