The scope of the project is what it is. Scope control is important; people who try to do more than is realistically possible run out of time, or money, or energy and the game is never finished. In contrast, this one just was, twice over in a way: the first content pack finished the game functionally and from a narrative perspective, and this third one finished all the content I had planned for it. Itch, Steam, and gaming in general is littered with the corpses of unfinished projects. Just last week while cleaning I discovered the stickers for a game called "Drift Stage" that I backed many years ago. Fun little simple game about drifting cars, the demo was already 80% of the way there, they had a bunch of buzz, a bunch of support, everything going for them.
Game never came out.
They couldn't. close. the. circle.

That's what's important. Finishing. Having realistic goals and completing them. If you make a small, humble thing and finish it, you can then go on to another, and another, and slowly build. If you get side-tracked trying to do more and more and more, the project crashes and burns, and after a few of those people stop trusting you, you lose your enthusiasm, and it's over. 

Of course GT could be more than it is. A game could ALWAYS be more. I know this very well; I MADE it. There are tons of other things I'd like to do, weaknesses I see. But in both drawing and game design, there's a principle of diminishing returns, like upgrading a computer. Up to a point, more and more memory, faster and faster processor etc gives a huge boost. After that, it drops off dramatically. Up to a point, working an image, or a game makes it dramatically better, but after that you're putting more and more effort in for less and less reward. This means that the best way to improve at art, and at games, is to know when to quit, when to let a piece be finished, because you learn more, and gain more, and make better stuff by moving on to the next thing, rather than trying to polish forever. 

Also realistically, there's a certain range, a certain league I can work within, given my resources. I will continue to tweak my art, my game design etc as I go forward, because I always want to learn and improve. I look at old art, and already see ways I've moved beyond it. Certain programming challenges that were intimidating before are now solved problems, and all that carries forward. But with that said, broadly, I expect future games to be roughly in the same range as GT. It's a good balance of what I can do with the time I have while still being interesting, fun and hot to enough people. Not everyone obviously. But enough.

And yes, it would be helpfully to have a team, but scaling, and working with other people is very difficult and dangerous, moreso than you probably realize. A project like this takes a lot of discipline and dedication to keep on track; if you have multiple people, they ALL have to up to that standard, on a consistent basis, AND you have to deal with the inter-personal nightmares of running a team. Some day I probably will have to work with others, and in small ways I already do: the excellent work of Openfireplace charting out the game paths, Eiga-xx translating it, and so on. But for now, it'll have to mostly remain solo. This is more or less the product I make, and will make for a while. A lot of people like it, but you don't, if it doesn't end up being what you're looking for, that's fine.