Let's put aside wikipedia being rotten with bureaucracy and obsession-driven bias, which is similar to stackoverflow preexisting flows before LLMs streamrolled.
Fact is, wikipedia is a human driven summarization engine of secondary sources, hopefully in a way that echos the sources consensus.
This is exactly what LLMs are best for, summarizing huge amount of text, and training can easily focus on high quality books and thus exceed wikipedia in quality.
It's enough to read an AI summary where the first line talks about the subject in hand, compared to wikipedia where the first line is the product of some petty argument about a political disagreement