> this "hawking index" meme must be a new-ish thing

TBF the methodology and hypotheses that it's based on aren't that bad. I'm sure Amazon has better data, but for a "publicly accessible" data (at that time) I can see it. The problem is that while lots of people might abandon the book, that doesn't mean that still loads of people don't read it fully. They are, after all, extremely popular books. Obviously some people will have received / impulse bought / FOMO / new year resolution / etc the books, but from the sales numbers that's still a lot of people that did enjoy them. Marketing aside, the book is pretty approachable, like were Sagan's books and so on.