The problems Wayland solve are those of yesteryear, sprinkled with the broken dreams that we'd all be running it on Linux phones by now. In that context a strict security model makes sense.

Trouble is, that security model makes no sense on today's desktop. In 2020, people aren't downloading and running native applications on desktops, not even (especially?) on Linux. The desktop is now solely a manager of browser windows. Everything that normal folks do is done through the browser, from email to office collaboration. Maybe a few Electron apps sprinkled in (mostly targeted for developers, ironically). Maybe the calculator? That's pretty much it.

The most important desktop apps today? Chrome and Zoom. Both which barely work in Wayland. But at least all that non-existent native desktop software can't now spy on my web mail? Too bad screen sharing is now a complete shitshow.

Actually worthwhile problems to solve on the desktop are for example high DPI and fractional scaling, rock-solid multi-monitor support, dynamically plugging in and removing displays, mixing displays of varying DPIs, high refresh rates and variable sync etc. The desktop will increasingly become a niche for high-end developer setups.