Having a knowledgeable shopkeeper to talk with on the other hand is really a fantastic experience for me !
This is a fairly rare experience for bookstores in some of the U.S. geographies I've lived in.
The shopkeepers I encounter aren't widely-read or intellectuals. They're either college students working at slightly above minimum wage to pay for school, or ex-hippies with lots of used books in their garage who figured they could make some money selling them. They have no sense of the intellectual pulse of today (they don't know what ideas are popular), don't have a good mental semantic tree of authors and their works, and worst of all, aren't readers themselves. I don't expect bookstore owners to have the omnivorous interests and breadth of Tyler Cowen, but they should at least have intellectual curiosity and a love of books.
The only exceptions are bookstores near great universities, where the owners tend to be stragglers who loved their university town so much that they stayed. They're usually former English lit, philosophy or other humanities majors who continue to read widely. You can tell a bookstore is good by the quality of their curation -- really good bookstores understand space is a premium and don't stock junk.
That said, you also need someone with a mind for business. Unfortunately this confluence of skills doesn't occur regularly so we live with what we have.
Another is the available of cheaper international paperback editions online.
For translated books, I do not find bookshops striving to carry as many different translations of the same work as possible, most carry only one, when some works like Homer and the Russians Greats are published in very many translations.
My point is rather than in France the advantages offered by the physical bookstores (namely, its friendly employers) outweighs that, in part because the online marketplace doesn't have a price advantage. Of course, in the end it's a matter of sensitivity to various criterias, stock definitely being a relevant one !
The problem with the large catalog on sites like Amazon is that it's impossible (at least for me) to sort through it if you are just browsing. If I'm in a bookstore I always find new and interesting books that I end up buying and enjoying.
That could have something to do with Amazon's sorting/searching features, which are so bad that the results are often comical, with random unrelated results intermixed with the thing you're looking for.
Default sorting is by the "Featured" variable, which probably means 'makes most money for the seller', rather than something that actually benefits the searcher. This is a guess, it is not defined.
I think they maybe, finally, let you sort items when you're searching outside of a specific category now, but that's a relatively recent development.
It doesn't help that less than scrupulous Amazon sellers are constantly changing products around so that reviews don't line up with the product description. That widget you've found with 100 five star reviews, well, it turns out that the reviews were for a different product, but you can't tell unless you go read enough of the reviews to figure that out.
In France, the software they use is more powerful than Amazon to buy books. The database is clean, deduplicated and well maintained by professionals that know each others.
That's part of it, but the price is a lot of it, too. I rarely go to bookstores anymore, even for books that I know I'll find there, because the books are more expensive than at Amazon.