I agree. But I am wondering, I remember linux had a lot of multiple Desktops, but somehow this fad never stuck. So maybe one Desktop was somehow a good idea?

I'm not sure fad is the right descriptor here. Unix WMs have had virtual desktops since the 90s (80s?), MacOS got them around 2006 and Windows in 2015.

Use by the non-initiated may not be that high, but that shouldn't be surprising given that user education is a very scarce resource and it's being spent elsewhere.

I meant as a default.

Aren't document tabs, eg browser tabs, an app-confined version of multiple desktops. The idea behind their are virtual screens of content you can switch between.

Every KDE I've installed (Slackware, Mandrake, Ubuntu, Fedora), to my recollection defaulted to multiple desktops.

I'm so happy Win10 has virtual desktops as in moving from Linux to MS Windows - mandated by my workplace - that was a massive pain point.

Don’t all major OS have virtual desktops now? A single desktop is very restrictive, it’s much easier to have some spatial separation between contexts.

It might not be the most visible feature for most users, but it is definitely an important one, which I would hate to see go away.

It’s not well known, but it exists. I can’t say exactly since when; it was a couple of years ago.