but not for an encyclopedia, which is, by definition, literally supposed to contain all knowledge

https://en.wikipedia.org/wiki/Encyclopedia#Etymology

The word encyclopedia comes from the Koine Greek ἐγκύκλιος παιδεία,[13] transliterated enkúklios paideía 'general education', from enkúklios (ἐγκύκλιος) 'circular, recurrent, required regularly, general'[5][14] and paideía (παιδεία) 'education, rearing of a child'

https://en.wikipedia.org/wiki/Wikipedia:Five_pillars

Wikipedia combines many features of general and specialized encyclopedias, almanacs, and gazetteers. Wikipedia is not a soapbox, an advertising platform, a social network, a vanity press, an experiment in anarchy or democracy, an indiscriminate collection of information, nor a web directory. It is not a dictionary, a newspaper, an instruction manual, nor a collection of source documents or media files, although some of its fellow Wikimedia projects are.

(emphasis mine)

We have limited time in our lives. "Everything" can be the goal of a library collection. An encyclopedia gets the important gist of the "everything" in a practically readable and understandable format, and directs you to other places where you can learn more if needed. A balance has to be struck. Sadly, I guess Wikipedia has become a symbol of all knowledge on the web, since most other places are so dogshit and uninformative, that we can now expect or demand it to do beyond what an encyclopedia should normally do.