I don't think the scope even needs to be scaled back, the dev just needs to work on it. It's just that simple. Notice how his shown no new pictures or anything in years at this point? Because he hasn't worked on it. The "code" part of the game is by far the fastest part of the game to make all things considered.
If I could merge the game in like a month or however long it took me, with how long this game has been on haitus now I could've easily remade the entire game, images and all.
Personally, it wouldn't surprise me at all if BlueCat was also Marche (I think that's their name) and just making that game instead since it's got a pretty similar vibe, and they're both german too I think. That's conspiracy land though.
Originally it was supposed to be an entire year in game, that could be scaled back. Also, he kept adding side characters because they were a privilege for people paying higher tiers, again, that could be scaled back to the core characters and a few extras. It does not need the fancy interface, either. The issue is, as you said, is that you could have redone the entire game by now. I agree 100%. If there were legitimate issues, they could have been solved by now, but instead we are left with this unfinished game. This is how the dev wants things, and for some reason, there are people still willing to support him.
This site has plenty of unfinished games, it happens. I can appreciate when a dev has the guts to at least to say they are ending things. Ghosting is annoying, but if your Subscribstar and Discord suddenly disappear on the same day, at least we can assume you are done developing the game. However, leaving a game in a perpetual state of maybe while keeping your accounts open but doing little to nothing is just wrong and offensive.