> The "document" was a central feature, a core OS concept. Isn't this largely the same in the modern desktop? File explorers do call handlers for each files.

> The "document" was a central feature, a core OS concept. Isn't this largely the same in the modern desktop? File explorers do call handlers for each files. But it's also true that the recent trends among apps half-killed the concept of file explorer - they use built-in search functions these days. It's good in its own ways, but often it's necessary to go through filesystem when working with multiple apps, which can be awkward in terms of data management. Also, many apps automatically save states on close. A problem is that the behavior is far from being standardized, and there are tons of different ways how apps handle their states. This usually gets really painful, as one must learn each app through trial-and-error.