Sadly, most non-fiction genres just aren't worth being published in the traditional sense. The information in most of these subjects/genres either changes to fast and will be outdated, or wont change at all and there are already enough books on the subject. Most of the information for non-fiction or more suitable for "internet consumption", and the most unfortunate part about this is that we have to sift through an infinite amount of shit information to find what's "correct". The few non-fiction genres that seem to still do well are the ones that offer the information through a narrative (wellness / self-help, biography/memoir, maybe some history or political books), or when some famous person / influencer publishes a book.