I agree. Ms Druckerman needs to read a lot more books. She should make a point of reading the classics of French literature starting with something simple like "Le Petit Prince", then Maupassant and slowly work her way up to "Les Miserables" which will take years, but she has the rest of her life to do this. Even if she does not absorb everything, she should press on. She should do this reading plan on a e-reader. I've been glancing at the comments here and no one mentions the fact that e-readers are a great way to learn a language. Why? Because getting the definition of a word by touching it is way easier than old-fashion dictionaries. She should also highlight the word she does not know and when she is done with the book email herself the highlights which e-readers allow you to do. In this manner she will build up her own personal vocabulary list. This plan will require some discipline, but it's what you have to do if you want to be more fluent. Technology makes it easier than it used to be thanks to e-readers and online dictionaries.
It's not like it's actually possible to comfortably read french books when you learn the language, with their specific grammatical tenses only used in literature. I speak French fluently and at home but I'd be incapable to read a complicated book in that language (while I'm absolutely able to read English books and do that all the time, and speak English way less often).
English books use different registers, vocabulary, and grammatical tenses than found in everyday speech also. Basically every language has differences in formally printed books and daily speech.
And it's not like you have to read dense texts only. There are plenty of short books, or books with lighter material, that learners can definitely read. It's a very good way to discover new vocabulary and see how words are used in what contexts.
Written English matches spoken English almost 1:1. Written French could as well be a different language (hyperbole, but not that much). "Just read books" is just not good advice in this case. Reading comics would work, maybe.
English is not my native language. I've been reading English books mostly for pleasure for years: when books main language is English that's what I get (thanks Amazon). At first it was hard, it is still hard when trying a book in a domain I've not encountered a lot. And I'm still reading faster in my language but there are not a lot of modern English books I'd consider impossible to read.
That's kind of my point. Your advice to read books to learn more words is right, in languages like English and German. It does not work well for French because the written French is too complicated and different.
Absolutely true -- but read BD's instead. That will give you spoken language, context and fun in one package. Forget about Maupassant, La Peste, Tartarin de Tarascon, Seigneur de Brantome, Victor Hugo, Balzac or any of the other ancient French classics. Ancient language, weird sentences and -- not much good as a read either.
Not reading books will limit your vocabulary. If you read when required, you don't read.