The heart of this piece is the author's realization that (relative to their cover price) glossy, expensive cookbooks don't actually cost that much to print: "Until one-day I got lucky. Just by chance I spoke to the print broker who actually worked on the exact bid for that famous book. And he told me precisely: that super amazing cookbook that I truly loved, which at the time retailed for $50 and had won every award…
Well, that and that their initial publishing offer (which is good? I have no experience) is more insulting the more you run through the numbers. On the other hand I've read accounts of people who've published through O'Reilly and were very happy with having a team of people to crunch through the layout, typesetting, etc.
That doesn't make book writing for publishers a good deal for anyone, by the way. Executing on a book contract is one of the lower effort/reward things you can do.