The success for me is the very writing you create. That you spend the time to sit down and craft all these words and put everything together around once a week is very impressive.
I'm certain it helps you to clarify your thoughts. And to develop new roads of thought. It's also nice to be able to look back at your archive. Just like you did with the lemonade search. See how you covered something (or not covered at all). The more you write, the more you can intersect things. And actually, that's one method of getting more subscribers. When writers demonstrate that their work is interconnected with their previous writings, it shows themes. It shows your investment, that you cover these themes in depth. Linking to previous articles shows that you care about your previous writings, and that means your future writings will be good too.
And the search engines like the interlinking. That helps the search engines do their job. When you interlink stuff, the search engines know better how your work relates to each other, and what the important topics are.
And the same for readers. The readers get to read more of your work that way. They discover more of your archives. They get more invested. The more invested your readers are, the more likely they are to share your work. And then your work spreads. From time to time I've linked to your writing from my site.
It takes time to interlink all your work. I haven't really done a good job on my site. Maybe I should do that more. But it all helps to develop a larger readership.
Which then leads to more engagement. That's really my primary goal with writing.
Speaking of engagement/comments, Substack is a curious land in that regard. I've seen some substacks with lots of comments. Some with very few. It raises the question if Substack is built for comments. The simplicity of the UI certainly helps to get more comments. (in comparison on my blog, the design is too bloated at the end of the article to get the comments).
However, I've noticed that when you post your articles on Facebook, that you get more comments there. And that's because Facebook is totally built for comments. That comment box is right there. Boom. You don't even have to scroll to the bottom of the post to leave a comment. Of course, that's weird, because people would leave a comment without reading the whole thing? Alas, that's how the internet works. Even with that point aside, that someone would comment without reading the full post.... Facebook's UI gets people in the mood to comment, because the comment box is visible right away. It sets the tone for commenting.
I've thought about designing my site to mimick that--having the comment box appear right away near the top. Just never got to it.
Now, to be clear, I'm NOT advocating that you post your full-length articles on Facebook. You aren't doing that now, and I don't need to get into all the reasons why to not do that, because you are probably already aware of that.
Ok, back to your point you feel like something needs to change to keep your own interest up. I'm curious what you are looking for. More subscribers? More comments? I'm guessing you'd like both. But with your writing, I also get the sense that you enjoy writing them.