It is possible that Google as an organization had enough foresight to see that search would eventually be eaten by AI chat bots and so intentionally degraded the experience of search to encourage movement in that direction. And also that Google was too dumb to actually ship their chat bot first and capitalized on their choice to sabotage search.

It seems a lot more likely that the the decline in the quality of search is due to a combination of hyper-optimization for revenue and difficulty combating large scale spam farms.