I'll start off by saying that I have no answer to your question.
But, personally, this game kept me entertained for at least 100 hours of my life and I've yet to fully complete it. I would buy it again on release, guaranteed. I'd go as far as to say that the game may as well have double the content once it is released on steam, given the sheer size of the updates and even re-textures that, might have not even been asked for or necessary, but they were still welcome and a testament of what's to come for this game.
I don't know if there's any background check that checks whether you've spent money on a project here on itch.io or not, but I strongly believe that the game could also be available here for sale, and those who have donated may receive the copy for free. But I'm talking out of my ass right now. I really hope it'll be on steam though, that way it would get way more traction. And I like my games on steam as well.