Short answer: because this is Hacker News, not Middle Manager In A Large Organization Serving A Well Established Market News.
The author went to the effort simply because he himself found it interesting. He published it on a hunch that at least a few other people would find it as interesting as he did, even if they are not working in that industry, just because technology is interesting in its own right. He was right.
that's obviously a tautological answer. I am saying, he is doing a lot of work, if he redirected this work towards something more relevant to more people, he would produce more results for himself and for everyone else.
It looks as if you're treating it as a means to an end. I would say that it was more of an end in itself. Sure, something else might have been more impactful to a larger number of people, but having an impact isn't the point.
The author went to the effort simply because he himself found it interesting. He published it on a hunch that at least a few other people would find it as interesting as he did, even if they are not working in that industry, just because technology is interesting in its own right. He was right.