The GNU project has always preferred to reuse available free components
instead of recreating them. That is why GNU does not have a display system
(Xfree was available under a free license) or a text processor (TeX was
available under a free license). That is also why the effort on the Hurd was
weakened a lot once Linux was released under the GPL license and proved to be
a better solution a few years after its beginning (debugging, hence
developing, micro-kernels is very hard).
All that to say that a 100% GNU distribution would not only inefficiently
work on very few systems (because of the Hurd) but it would also be very
incomplete. The graphical GNU packages would not even be available because
GNU does not have a display system! Who would prefer such a system to
Trisquel?
If it looks obvious that a non-GNU display system (Xorg or Wayland) is to be
used, why not also preferring Linux-libre to Hurd, i.e., what is the argument
to prefer a GNU package to another *free* alternative that is technically
better?