Such a small market. If the "money has to be right" they should bring it to all consoles first then port to less-gamer-centric computer OSs.
The cost of bringing the game to those platforms is minuscule in comparison with pretty much any other platform, specially consoles. Pretty sure that stretchgoal is just there for people to feel like they achieved something (of course there's still some effort involved, but I think out of all the stretchgoals they're planning, that's the cheapest one).