> When there are plenty of ads, the maker of the best air fryer now has to bid on ads as well, if only to protect the sales they were entitled to in the first place. Businesses continue to buy the ads—not because they’re dumb, but because the system has created a situation with few options.

Sure, this is probably accurate in many situations.

> The highest-yielding ad my publisher has tested so far [for Seth Godin's new book, The Knot] is the search "Seth Godin The Knot".

But not that one. If you cut spending on that ad to zero, you would lose an immeasurably small number of sales. The ad is high yield because people who search for "Seth Godin The Knot" are already planning to buy Seth Godin's The Knot. Letting other people display ads on top of that search won't dissuade them.