Well folks, it’s the beginning of a new era: after nearly three decades of KDE desktop environments running on X11, the future KDE Plasma 6.8 release will be Wayland-exclusive! Support for X11 applications will be fully entrusted to Xwayland, and the Plasma X11 session will no longer be included.
Well we used to need a way for work to be done centrally because powerful matches were expensive. So X11s idea was just do everything remotely and draw the results locally. Then machines go cheaper so X11 was modified to render more locally processed stuff.
Now, we have thin clients, Citrix, and Remote Desktop what are much less efficient than the old X11 approach.