Druckerman has this to say:
"What underlies France’s book laws isn’t just an economic position — it’s also a worldview. Quite simply, the French treat books as special. Some 70 percent of French people said they read at least one book last year; the average among French readers was 15 books."
This is an inadequate explanation. See the Pew Reading Habits Survey:
76% of American adults have read a book in the last 12 months. The average over _all_ adults was 12 books (but remember, that includes non-readers as well, whereas Druckerman's wording suggests her average is of readers only).
There are bookshops everywhere in France because the agency model has been enshrined in law. It is protecting an old way of doing business by protecting the margins of entrenched incumbents from new competitors who can get by on slimmer margins. If that's what you want to do, okay, hey, countries have jurisdiction and all.
But don't argue that France is this way because they have magical, special love of books, unlike us barbarians. We love them more -- we read more -- at least by one metric.