I mean, they aren't obligated too and most devs I've seen that have public releases on itch don't have a paid version on itch with it, it's almost always patron or subscribe star, plus with patron you can just pay the small amount and then stop after you download the files if you really want to, same difference than doing it here just a small bit less convenient. I haven't played the game yet so everything I'm saying isn't even related to release time or quality, just of what is the norm. Also money? yeah of course a huge drive is money. It takes a lot of time effort and cash to make these games/projects. Greed? honestly not sure yet but yes of course itch is used as advertising. It works and is simple, but it's also in combination with itch being a necessary place to show your work and hope your name sticks. like do you think most NSFW artists/game makers do it for the good of the world? you expect far more from these usually solo devs on itch.
Edit: just did a super quick look at the patron and there devlogs and pictures and discussions and whatnot every few days it seems so they definitely aren't ghosting. although I do understand the frustration for the wait time I would probably give benefit of the doubt that both the update is going to be good and also theres probably things going on irl that are occupying them but i'm not sure so thats a bit in the air for me as I didn't look super deep into it.