> 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.

What geographies?

Don't want to be too specific, but let's say rust belt cities with no top ranked colleges.

Most commonly in physical stores, one often finds that, in a multi book series of books, volumes are missing or not available, good shop managers may be trying hard to avoid that situation, but I think it is a pretty common thing. This problem can only be worse with comics, graphic novels, most of which come in serial volumes.

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.

There's no denying that the "online" catalogue will always be larger than what a physical bookstore can have in stock.

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 !