I tried checking through all the official marketing and updates to provide evidence it was changed to Steam-exclusive but couldn't find any, though I swore I had read something officially saying that... I'm not the type of person to say something like that without solid confirmation, maybe I got mixed up with another game...? Sorry, this is very unlike me. This site says we have access to the files from here (or, y'know, at least the Standard Edition... hopefully that'll get sorted or we'll be able to add the mysterious extra $2 to the original price of the Special Edition we already paid for), so I must be wrong.
This game is definitely in development hell but I still have complete faith in Team Precatio. It'll take a long time but I'm willing to wait. As long as we do get it, someday, to at least the same standard of quality as the demo, I'll be happy. In the meantime I can stare at Guillam's mad pecs.
EDIT: Ahhh, I went through all those pages of updates and all I had to do was scroll down a little on this page... h-hahaha, sorry, here it is, in fact they told you directly themselves, I guess we both forgot.