The educational and informational queries were always the least valuable from a monetization standpoint. Chegg Answers could rank for these low competition (also low commercial intent) terms-- think queries like phrases from textbooks students would be querying. There is virtually 0 way (for people besides Chegg) to monetize these types of queries. Now Google can answer these queries directly, albeit with the assumption it costs them slightly more to serve these AI responses than a search query.

AI overviews are breaking the implicit "contract" for informational sites-- "we will create content to rank on Google with the expectation of monetization via display ads, mailing list growth and/or sales commissions of some sort." If these sites now lose 90% of their traffic, they simply go extinct. We have already seen the destruction of the old web era sites and the walled gardens being built. How many new sites, at the same frequency as 15 years ago, 1) get built and 2) get visibility without relying on one of the fickle walled gardens for an audience?

Google will probably figure out a way to monetize these informational queries by building better profiles of users. Or most likely, they start slipping in commercially biased responses-- either natively or disclosed, but probably based on all user conversations instead of the current one.