The official apps are all open source (GPL-3.0, https://github.com/ProtonDriveApps), so even though a formal API isn’t documented it is derivable from the 4 available clients. This is how rclone added support for Proton Drive. So there isn’t really anything stopping GNOME or KDE from supporting it.

that’s a good point, too. they would have that moderation control over an official lemmy community, too. But obviously not on any unofficial communities.

Yes but that’s not supported by Google. If your going to ding Proton Drive for not having a natove Linux client then you shouldn’t tout Google Drive as a competitor who does, as they don’t. You’re giving Google Drive a free pass because of a third party. Google and Proton are the same on this feature and you should disparage both services equally as a result.

All that matters for decisions like this is the quantity of customers (actual or potential).

Google does not support Drive on Linux.