Well, you seems to assume that nobody wanted a book about giants so yeah, I can only assume that you are basing this assumption based on your own personal preference and anecdotal evidence (you never seen someone specifically said that they want a book about giants hence nobody wants it).
The only way to judge if a book was wanted or not is if the book sold or not. If it sold, then there was demand, if not then there was none…
And here we are talking about a company that is supposedly making products as cash grab… but making a book takes time and money, so if there is no demands (read that nobody is interested), how can it be considered a cash grab if they don’t think it will sell?
If they made a book about giants, it’s because they considered that there was a demand for it.