Initial summary: There is no link /var/lib/X11/X to the correct X server
binary.

To reproduce:
1-online upgrade (zypper dup) from 15.0 to 15.1alpha
2-boot multi-user.target
3-login on any vtty
4-startx

Actual observations:
1-error message: "There is no link /var/lib/X11/X to the correct X server
binary."
2-/var/lib/X11/X does not exist
3-/var/lib/X11/ does not exist
4-Xorg session does not start

Expected behavior
1-Xorg starts normally

Comments/Questions:
1-graphical.target works as expected
2-startx works as expected following manual creation of symlink /var/lib/X11/X 
3-startx continues to work as always in Debian Buster & Fedora Rawhide,
apparently still "supported" and extensively used. Isn't it a standard
component of upstream Xorg?
4-Why does startx want /var/lib/X11/X (which exists on neither Buster nor
Rawhide) rather than existing /usr/bin/X or /usr/bin/X11/X?