How do you know people won't buy it? In the last 30 days people donated € 152. That's not much, but it's something. And no, I'm not saying spend that. I'm saying that at the minimum there are people who probably wouldn't mind buying a book to support the game. I know I've donated before, and rather than a title that lasts for a bit and an extra drone, I'd actually have a physical, tangible object. That'd be awesometastical. Even better if there was a signed copy (yes, I'd prolly splurge and buy that instead of the regular one).
You could always just ask people if they'd like it. There are ~400 active daily players of BM (pulled from BM stats), another ~300 on top of that that consistently log in atleast every few days. That's ~700 people you can ask whether or not they'd like something. You could even ask them how much they'd expect to pay for something.
If people aren't willing to spend less then $10 on the digital version and count it as a donation, the chances that a substantial amount of player base would pay more to get the physical version is unlikely. Sure there will be some, but enough to make it worth Toms time and effort?
Poll