You sell 3x as many books that way.

I bought two of the Fate books (first the "toolkit" book, then the "core system" book) not fully understanding the differences.

That's not really relevant to board games, though. Rules all free for essentially every board game.

The Fate books (at least several of them) are also free to download, with some Creative Commons license or similar, so you can read the rules without having to buy anything if you do not want to.

"...and one book to rule them all"

"...and in the darkness bind them"

Please. Ring-bind them.

It's the only way that they'll lay flat when open

I first read that rhyme 50 years ago and I have never spotted that before. Well played, sir

The latest edition even comes with token ring wraiths.