great...1 step forward, 3 steps back...why every unity and unreal engine project must be this way...see you in 5 years !
Unity and Unreal are... Deeper, then a lot of game systems. Look at the major alternatives: RPGMaker is expressly about making a classic top-down RPG with Final Fantasy sort of mechanics. Ren'py is focused on Visual Novels and point-and-clicks. They're able to be engineered more tightly for those things and in exchange it's difficult to make an RPGMaker VN or a Ren'py Shmup.
By contrast Unity and Unreal are more wide-based and can be used for a lot of different projects. They have a lot of bells and whistles, most of which aren't applicable. They require from the developer a much greater understanding of their own project and how things will work as well as the developer's understanding of Unity and Unreal Engine themselves. You can make a top-down Final Fantasy-like, you can make an ASCII roguelike, you can make a VN or you can make a FPS or Brawler. Hell, I'm currently in the process of making a free-roam blobber, a genre which as far as I can tell has been dead for over a decade.
As a sort of counterbalance to how powerful the engine is, it's more complicated to learn and use. It requires more stuff. A lot of Patreon projects are from people who just decided one day to try making a game, and they usually have loose visions of what the game should be or how it all fits together. They often have little to no experience with Unreal or Unity's systems. The games wind up kludged together, the code and the blueprints both spaghetti'd harder than an Italian restaurant after a tornado. And when the dev decides they want to change something they're faced with their own, months-in-the-making mess and a lot of them just
give up.
There's no malice here, no scam or conspiracy. It's just what happens to 99% of games in development that aren't peoples' literal jobs. When there's a suit paying you money to make a game you stick with it
because that's your paycheck and because there's half a dozen or more people to help you sort out what's going where, most of you probably have experience too. If it's just you, and you're only making Patreonbux on the order of being a frycook, when you've got another job that's really paying the bills and this is just a passion project and the passion is running low... There's a lot less motive to stick around and straighten your spaghetti. Especially when you can just move to a new project.
It's how indie scenes work for almost every creative medium. Look at fanfiction sites to see a similar thing happening with novels written by amateur authors. How many indie movies do you think get half-done and then never get finished?