Earlier quoted context omitted.
Wayland has a philosophy of "every frame is perfect", which means fixing every race condition. However, X11 doesn't have this philosophy. If the window manager is slow and doesn't respond to a notification that a window has been resized, drawing the new window content over the old borders is the correct thing to do . What sense does it make to freeze the whole display just for a window border? Similarly, tearing gets…
The races I recall being described were substantially worse, but that’s largely beside my point. My point is that, now that bare fillrate and framebuffer memory haven’t been a limiting factor for 15 to 20 years, it is a reasonable choice to build a desktop graphics system with the invariant of every frame being perfect—not even because of the user experience, but because that allows the developer to unequivocally cla…
This is not a given, though. It's entirely feasible to have a stable "display manager/server" with an extension/plugin system where your WM of choice would sit. Crashing the latter should not bring down the former.