Most embedded graphical Linux applications don't use X (X Windows System), instead they use framebuffer directly or any library such as Qt Widgets or QtQuick/Qm

Most embedded graphical Linux applications don't use X (X Windows System), instead they use framebuffer directly or any library such as Qt Widgets or QtQuick/Qml that draws on top of the framebuffer device file. So, there is no need for developing a new Window system that can work on both Desktop or embedded systems.