sienar said:
There is nothing assumed about the rule of halves. It’s a known method for estimating costs for books.
I can say with absolute certainty that “half, then half again” is as solid a rule of thumb as is possible to have.
There’s some variation, based on specific publishers (I suspect, for example, that Scholastic gets better than 25% of cover cost from its distributors for the Harry Potter books), but not much.
The game trade is slightly different (game trade distributors take a larger chunk in many cases, and retailers take a smaller chunk—25% to 30% instead of 50% of MSRP), and a select few game manufacturers are able to direct ship, so they get a bit more of the % for those sales (though when they sell to booksellers and retail chains, that’s generally through Ingram and the like, where they get book %s), but it’s still a reasonable rule of thumb there, if with a bit more deviation.