Qts design supports many window targets and they're not going to desupport one with millions of users.

It's an entire extra code path they have to maintain. If they could tell those millions of users "for God's sake, it's 202x, use Wayland instead" and remove that entire code path, you bet your ass they will.

Since they've written all the tests already and have many billions of hours of execution, that sounds unlikely. And if you look at the history of how QT has supported things it seems very improbable. I would expect QT to support x11 for another 20 years.

I don't expect X11 to have any maintainers or contributors for another 20 years...

> Who's to say Qt won't drop X11 functionality also?

Corporate users. There's zero incentive to cut functionality out of a commercial library, so they'll probably gladly support Xorg until their customers stop paying for it.

Their big corporate users (mostly automotive) are on Wayland since ages, which is far easier for them than for a regular desktop user as they have a very narrow feature-set to support and have full control over what's required.

I think you grossly misunderstand who's paying for the Qt library.

Obviously it's not anyone who is willing to pay for maintenance of the X server and all the X libraries. If those stagnate and become broken, then they will likely remove the X backend.