This a Linux thing. Essentially, in an operating system you need a way to "draw" things on the screen. And a way to properly "move" the boxes "draw". Previous

This a Linux thing. Essentially, in an operating system you need a way to "draw" things on the screen. And a way to properly "move" the boxes "draw". Previously, the usual* way to do that was using XServer (XOrg). Now you would imagine that the server would take commands from applications, and would draw them. But it was the inverse (for various historical reasons)! However, the most egregious thing was that it ALWAYS ran as root. And while tries had been made to reduce the attack surface, it had to fundamentally change (I am skipping over other parts related to performance, scalability, or future proofing). And that's where Wayland comes in, and literally flips the whole thing on its head. Now the issue is XOrg has been around for maybe 40 years or more ! And that was not going to change easily. Distros did their absolute best to allow double use, but adoption grew very slowly. Eventually, supporting and testing for two envs will grow complicated. Anyway long story short, almost everything about Wayland is better IMO, actively supported and is the future. But migrating to it has been complicated because they were undoing 40 years of habits, hardcoded bugs that grew into features, and had to come up with new testing. This is something I typed up rather quickly so please take a peek at the Wiki page for Wayland you will find a much more complete history