That's what I mean though.

I've not used gnome for years, but I have a vague memory of gnome/mutter running on a single main thread which used to lock up quite a lot (javascript etc). And because in X it was X that used to manage things like rendering the mouse pointer every frame, whereas in Wayland it flipped to mutter having to do it directly, the stalls were way more obvious in wayland than X, which is where I think a lot of this perception came from.

Again, not sure how much of this is accurate, but that's the point I was trying to make.