The Firefox one might be a good analogy to continue: a window manager is akin to a web extension. They are browser-dependent, a firefox one won’t work on chrome, and vice versa [1]
Gnome/KDE/wlroots are akin to separate browsers implementing the same (HTTP) protocol. It’s a lot of work, plenty choose to rather fork an already existing code base (chromium based ones), but with time people will consolidate on a few ones. But you surely wouldn’t want an all-Safari, or all-Chrome browser “ecosystem”, right? (Though unfortunately we are not far from the latter). That’s what Xserver gave practically.
[1] There is some compatibility but let’s forget about that for now.
Gnome/KDE/wlroots are akin to separate browsers implementing the same (HTTP) protocol. It’s a lot of work, plenty choose to rather fork an already existing code base (chromium based ones), but with time people will consolidate on a few ones. But you surely wouldn’t want an all-Safari, or all-Chrome browser “ecosystem”, right? (Though unfortunately we are not far from the latter). That’s what Xserver gave practically.
[1] There is some compatibility but let’s forget about that for now.