If an authorship of a book is under a feasibility study, what the importance of the authors being very well known in the specialty related to the book, for the success of the book ?
Surely the reputation of the author works to a larger extent.
And also helps the publisher to "fix" the price of the book on a higher notch initially and to make arrangements for multi-lingual translation, electronic version, etc.
In addition to the reputation of the author, the following factors are equally important: the reputation of the (academic) publishing house, academic listings, digital availabilty of chapters and whole book via digital libraries like jstor.