The major difference between Program Files and, say, /usr, is that the former is split up according to "which program it belongs to" and the latter according to

The major difference between Program Files and, say, /usr, is that the former is split up according to "which program it belongs to" and the latter according to "what kind of file it is". Each scheme has its merits, and both are quite fuzzy ("is this helper a part of my program, or standalone?" "should this asset go in 'share' or 'lib'?"). Interestingly, the /nix/store directory on NixOS is split according to package, so acts rather like Program Files. However, I try to keep my browsing of /nix/store to a minimum, since it currently contains ~25000 top-level directories. Search (eg. wildcard paths) is still necessary, even with this level of categorisation!