But one really important structural factor is that books must be sold at the same price, by law, everywhere (+/- 5%, price fixed by the publisher. So you may pay -5% on Amazon or a retail chain like FNAC compared to a local book shop). This law dates back from the 80s, when book shop retail chain FNAC started to get very successful.
Add to that a very efficient book logistics system, and it’s often as fast and nearly as cheap to order a book and get it at a book shop than with Amazon.
It’s not all rosy as the system is very concentrated and vertically integrated on the publishers and distributors (wholesale) parts. These publishers+distributors combos get the major part of the revenues, and it’s in their interest to push a crazy number of new books every year (with something like 30% of the stock getting destroyed every year. Book shops can send back books easily and get refunded)
Authors and book shops, at the two ends, get a very small percentage of the revenues. French authors are totally dependent on their publishers for every step, from editing to publicity, and usually license all rights from the get go. Book shop have very small margins (I read around 2%!) and even just loosing thrillers or another popular segment to ebooks might make hundreds of book shop collapse ‘suddenly and unexpectedly’…