Just to give credence to the OP's point for a sec - make no mistake, this book could only have been published now. It's not happened, as far as I'm aware, with other photographers (like Maier) whose output doesn't have a basis in self-portraiture? Not that I'd want to see it, but there isn't a Harry Callahan self-portraiture monograph for example - another semi-enigma of her era (who also has self-portraits in his published oeuvre). People are more interested in her - as has been rightly said many times on this forum, but also, there's a massive audience for self-portraiture now which has only appeared in the last few years. The book then has a cynical selling point as far as I see it - one that seems borne out of our obsession with the lives of troubled celebrities via Twitter selfies.