Because `tty1` is active when `xinit@user.service` starts on `tty7`,
Xorg cannot bind the modesetting driver to the DRM device:
> (II) systemd-logind: got fd for /dev/dri/card2 226:2 fd 13 paused 1
> (EE) Error systemd-logind returned paused fd for drm node
To fix this, we need to start Xorg on the active console.
Another potential fix would be to run `chvt 7` before running `startx`,
but running the GUI on tty1 seems to be what the major display managers,
e.g. GDM, are doing now.