Here is an observation from our experience at Jellybooks Ltd. when doing reader analytics for non-fiction books:
Completion rates are abysmal for this type of book, so you would think people would want and would value shorter versions, but we found the opposite to be true.
Readers did not value the shorter versions (they compete with free blog posts and similar). They wanted the “full length” version. They pay for the optionality to dive deeper, the option to read it some day later, or, if the printed version, the value derived from displaying the book on their shelf (to show off, whatever…).
The value proposition of non-fiction books is very, very different from that of fiction books where reading the work from start to finish is all that matters. Non-fiction is radically different in that respect.
So one of the quesitons I would ask myself if I were in your shoes is: how do I best monetize a service that sits between free blog posts and “full length” books, because that’s the real enigma here.
Framed differently: the miracle in an age of abundance is how much readers are willing to pay for “traditional” books ($150 billion per year of which more than half is “trade” or “consumer”), but not for any other form of content.