I'm caught in the middle due to being on a budget. I like highly technical publications. But I am older with a limited budget living in the middle of a pandemic which has made things more expensive and harder to get. So budget directly impacts what I can buy, not always what I want to buy. I am not alone in this regard.
Perhaps highly technical publications have a smaller market, sell fewer copies, are more difficult to publish therefore more costly to produce, and consequently cost more compared to simpler, more narrative books that tell a story with few if any images. Therefore, highly technical publications are often beyond my budget, unless found somewhere on a discount or bought used.
For example, I'd like to own the AOTS Queen Mary book and the newly revised AOTS Yamato book. They typically price out at $50-60 or more. Too much for me so I have not bought either.
Because my budget is limited, I can only afford far less costly references than new AOTS or similar publications. Therefore, I buy only those references that don't break the bank and I can use to help make a better model, such as Classic Warships pubs and Squadron "On Deck" or "Walkarounds". Those publications provide usable information for modeling purposes and are comparatively affordable for modelers like me on a budget.
Obviously, other buyers with a larger budget would certainly buy an expensive, lavishly illustrated, exhaustively researched, highly technical book in a fancy binding.
While thrust blocks and other machinery components are interesting, drawings of them accompanied by detailed discussions of them don't translate to usable information to the typical ship modeler. Certainly, cutaway models do exist and thrust block information would be valuable to the cutaway ship modeler. But how big is that market?
Perhaps the questions to consider are, "how big is the market for the information my book offers?" and once the size of the market is reasonably understood, "will there be enough sales from that market to pay for the publication?".
Maybe the book is a "labor of love", and making the author a profit isn't the real goal. In that case, publish away and don't worry about the market.