[throwawaymlc]

That's cool, I hope it works out for you! I've thought about this kind of thing too.

I think for most mainstream programming languages, the market for books, blogs, tutorials, youtube channels is pretty much saturated. However, I have worked with several proprietary / vendor products over the years that have perfunctory documentation, not much in the way of a user community, where serious users end up having to experiment + reverse engineer things to get it working well.

I think it could be interesting to become a third party "expert" for such a product, blog about tips and tricks, offer training and consulting, write books, etc. I guess it's the same as what you're doing, just not for a "popular programming language", but for something slightly specialized but still actively used.

[quickthrower2]

Yes indeed, while the market for say Python books is saturated, there might be room for a Python for X, where X is some shared characteristic. E.g. Python lessons to prepare for a coding Bootcamp.

The vendor product idea sounds good. I think the money there is from consulting or software products, as the book won’t sell in volume. However the book can position you as the expert so people buy other things from you.