> I wonder when we’ll start calling them “Office files”.

Probably around the same time the save icon becomes something other than a 3 1/2" floppy disk.

English is evolving as a hieroglyphic language. That floppy disk icon stands a good chance of becoming simply the glyph meaning "save". The UK still uses an icon of an 1840s-era bellows camera for its speed camera road signs. The origin story will be filed away neatly and only its residual meaning will be salient.

Nowadays I’ve noticed fewer applications have a save icon at all, relying instead on auto-save.

And some only save to the cloud, whence a cloud icon with an arrow. (Not that I like that, but... that's what we get)