I'm older, familiar with how software projects fail and VERY VERY familiar with this attitude. It's not healthy for you, us or the product. I literally hope you just see this and not respond, just think, really think about what I'm saying.
As sure as you being unable to properly operate without shelter, food & love, this project cannot exist without its supporters. Taking arbitrary decisions is BAD for supporters as a whole. You will always have sycophants but they are marginal and not what I'm talking about, they are not the ones feeding you the bulk of money. By inserting so much time between releases you artificially limit your supporter mass for literally no good reason. What is most likely you're doing, is you're overcompensating for some failure you "know" you have "in your blood" to get things done efficiently, by being a perfectionist and making sure the product is beyond reproach even though it's late (or at least I prefer to think about it like that because in the alternative you're no longer the nice guy). Don't do that, it's a sure fire way to soon burden yourself with more than you can take. And then what? We don't want what comes next in this case. Don't doubt that this leads to a dead end. You are human and you have HARD limits that you must actively manage.
Notice those reasons you give, notice the pattern. You retreat in this argument of "artistic integrity". You're a hero, who works night & day for EXACTLY his vision and everyone else can go to Hell if they don't like it and you'll be following them soon after wearing this shiny thing you made for you. FUCK THAT. Don't think like that. Most of your supporters care about the product and, at the very least by extension, they care about you. There is no good reason to alienate them like that.
I don't know how much you kept up with Summertime Saga, but a VERY similar problem led to a complete derailment of that project. I'll explain it a bit, maybe you can better see the problem when it's outside, even though it differs in detail. First, years ago, it was an "executive" decision (just like yours) to keep the "artistic expression" free so DC reserved the right to keep changing the game everywhere with each new release. This impacted both the code base and the existing assets (images) because an ever increasing chunk of time from every release was spent with retouching old assets and code paths. In turn, this led to a catastrophic inability to make saves work across releases (i.e. to be able to resume play in vNext using old saves from vPrevious) because the decision worked directly against how Ren'Py games are supposed to work. It was a monumentally stupid decision taken with 100% arrogance just because the dev could. Was it fair to his supporters? No. Absolutely not. Supporters were expecting a story that goes somewhere and instead they got something that only goes towards the next paycheck. And with SS the arrogance didn't stop there, there was more, much MUCH more. The dev promised a "Tech Update" that was supposed to be done in about 8 months, to upgrade the game resolution and improve the code base a little. 2 years later they simulate work being done every few days by posting wallpapers, the promise has not been met and the project is falling apart. This is where arrogance leads (though I fully expect that in DC's case there is also a pure desire to simply exploit his supporters and his unexpected success for however long it may last).
I have no reason to suspect you're not doing what you're saying. But you have to deliver more often NO. MATTER. WHAT. It will most certainly be good for everyone, you, us and the project, including your artistic vision, I'm ABSOLUTELY certain. Between delivering once every 1-2 months and once every 18 months there's the mother of all middle grounds. Every 8-12 months is a LOT better than this situation. You most certainly can split the story to fit and I guarantee you this way will get you more supporters and we are essential to this project becoming greater. No matter how great a vision you have, if you have a health problem or you don't have food or shelter, your vision doesn't matter, it won't become more than something that will barely keep you warm, if even that. It's the same with this project. If it's not properly sustained by the most people that it can attract, the project will just fizzle out and die. I know we DO NOT want that and I hope you realize you're the key in this equation because if you keep deluding yourself that you'll pull it through somehow and that's all that matters, we're all fucked.
Again, don't consider this as an invitation to an argument<>counter-argument discussion. Literally everyone knows that you can do whatever you want with this project. Just take a moment to deeply consider, in a fruitful way, that just because you can do something, doesn't mean it's right or that you should do it. Listen to your supporters. They are also part of this project.