Why KDE's KWin Doesn't Integrate Weston/QtCompositor For Wayland Support

KDE developers have been porting their Plasma 5 + KDE Frameworks 5 stack over to Wayland, but at this point it's not nearly as mature as the GNOME Wayland support. As such, KDE developers have to fend off questions from time-to-time why they don't "just integrate QtCompositor" or the Weston library for speeding up their efforts...