Content like this has to choose the point they're targeting on a rigorous-education-to-entertaining spectrum.
Chess teaching content that's only for people at ~2300 ELO on how to get from there to 2400 ELO? Potential audience of perhaps 10,000 people worldwide.
Chess-themed entertainment content, with educational content mixed with lots of jokes and memes, accessible to players at all levels? Potential audience of 10,000,000 people.
Likewise, you don't become a bestselling business author if your book on how to be a Fortune 500 CEO only has an audience of 500 people. If your book succeeds, 99.95% of your sales will come from people who don't ever plan or expect to become a Fortune 500 CEO.
It's interesting you use that analogy because my dad was an author of chess books. Yes, many were a niche within a niche and only sold a few thousands copies.
My observations about business books match your intuition—the more popular business books tend to be popular for reasons beyond their educational content. They usually include great storytelling, are meticulously crafted and edited, and are about societally interesting subject matter beyond the pure educational aspects.
But that really makes a difference in your experience as a reader. I'm not saying popular means good. I am saying that on average with all things considered the popular business books tend to be better experiences to read than the unpopular ones. Of course there are exceptions.
One difference is that the chess content you talk about does have educational value - it will make you better chess player although in time ineffective way.
Chess teaching content that's only for people at ~2300 ELO on how to get from there to 2400 ELO? Potential audience of perhaps 10,000 people worldwide.
Chess-themed entertainment content, with educational content mixed with lots of jokes and memes, accessible to players at all levels? Potential audience of 10,000,000 people.
Likewise, you don't become a bestselling business author if your book on how to be a Fortune 500 CEO only has an audience of 500 people. If your book succeeds, 99.95% of your sales will come from people who don't ever plan or expect to become a Fortune 500 CEO.