" Instead of thinking of it like building a house, think of it instead as making soup, or playing Rachmaninoff. Adding an extra chef does not make the soup cook faster. Adding more pianists doesn't speed up the tempo of the song.
Granted, more musicians does make a more robustound (usually), but the man wants his shit done right, and he's got at least a wife, if not kids, to take care of. Why give up a piece of your pie(money) on what may be sub-standard help from others? How much time gets wasted finding out if other people are up to your standards?
Yeah that's not true at all, lots of people work in the kitchens of good restaurants, the better the restaurant more people you'll find in the kitchen because better food usually is more elaborated and needs more steps.
Yes, the soup cooks faster because you can have one guy cutting vegetables and another mixing the sauce and another peeling potatoes at the same time instead of one guy working step by step. They are doing low level work under orders of the chef but the chef does the recipe.
Playing a song faster makes no sense, music is written to be played at a set speed but composers have aids too, some of the work is mechanical and burocratic. You can be a great musician and a bad composer, a great composer and a bad musician. Why not find the best composer and the best musician. But this example doesn't really fit to a game.
Art can be collaborative without losing quality, we have music where the artist get together with other musicians, a producer (or a dozen nowadays), a sound engineer, and many other professionals. The quality usually goes up because these people are professionals that know more of their trade than one-does-it-all. We have movies, a VN is quite close to an animated movie, nowadays they are done with 3D software like Maya and 3dmax (tools like Daz but more advanced), well there are lots of people working for Pixar and of course the quality is higher. Pixar or Studio Ghibli don't do low quality work. And of course we have games, some with only one developer and some with hundreds.
BUT I agree you need different skills, if DPC can't manage to lead a team it can be difficult . But It can be done, that 'lone artist does it better' is just not true with a game that has a lot of low level work that can be outsourced, and yes he can do it, he just chooses not to. I don't blame him if he wants to keep the money for himself, he works really hard for it and delivers.
Anyway it's his Game, his Patreon, his Way. I have to respect that and we don't have a say in what he does with his work and he is stubborn as hell. I'm okay with him doing it alone, I love the game anyway.