I believe the problem was that if you did /google or !google on your bots for various chat platforms, you were able to find the top hit or two without ever looking at Google's Ads.
So the question becomes, how much potential money were they losing through the API? Does Google think that by removing the API, people are now going to go to another window, perform a google search, and intently study the advertising before reviewing the search results?
You just made a textbook strawman. It doesn't do anyone any good to theorize about what the dumbest possible reason might be for Google to do this. It is infinitely more useful to think about what rational, informed reasons they might have for doing it (regardless of whether you agree with those reason). People reflexively jumping to strawman arguments is probably #2 or #3 on the top ten list of Why We Can't Have Nice Things, in tech, politics, and just about anything else in the world where different groups of people have imperfect knowledge about each other's activities and motivations.
