Ghostbreed: Too expensive my ass. They could revive Shadow Warrior, which I think is even less popular than Blood.
Popularity has not that much to do. It's just they own the game. They haven't anything planned but they don't rush the money. So, when Devolver contacts them, they aren't really that interested.
Just imagine you have a lot of cool boxed games which you don't really use, but there they are. You own them, they are cool. You are also loaded and have another business, so you can afford to just sit and look at them.
Then I see a game you didn't even remember about and want to buy it. You don't really need the money, so what you do you say? A gazillion dollars! If I buy, l33t, you got a gazillion dollars. If not, which is the certain case, you still own the game. So you can release it, burn it, sell it, turn into a comic... Whatever, it's still yours.
In fact, less popularity may result in less restrictions. I haven't dived too much, but read
this. Shadow Warrior is open source and Apogee literally says they aren't interested in commercial exploitation.
So, in my personal (and not that investigated) opinion, the problem with this game is that it's owned by an asshole company which retains the rights just for the shake of doing so. As you probably know, J.Hall wanted to remaster the game (for free and even paying from his on pocker I remember to have read), and they denied it.
So yes. Fuck them.
PD: I also take this chance to post
this, in case you or anybody reading this didn't know about.
It is a total conversion, with the eDuke sourceport. So, it's not really Blood. But, as far as I played (which is the first chapter mostly), it is recreated quite nicely, not like those horrendous Doom Wads. Even if it's not the same thing, it really FEELS like Blood, and runs fairly better than the original. Not a substitute of a real re-release, but worth checking out if you want to try the original with a little of nowadays magic, like real mouselook and being able to play at your monitor's native resolution without lagging.