> aybe if you just dump a large number of unsorted files in place and do nothing with them. With a decent file manager and an hour or so, you can add many books and symlink them to the metadata directory with no issue.

Alternatively you can use a program's built-in library with no time cost to yourself...

> With a decent file manager and an hour or so

An hour? You've made my case. It takes at most a couple of minutes for importing hundreds of books in Calibre. Metadata retrieval is automatic (from the file itself and/or online). Everything happens in a few clicks.