One of the things I've enjoyed about the CBS era is the group's focus on peaking at the right time. Have the team playing its best ball at the end of the season. The things that go into that are chemistry, playing time, working out roles, etc.
By the time the playoffs roll around, if GH is still an average (or worse) rotation player, I expect CBS will shorten the leash. I don't think they know if GH will be his former self by the playoffs or not, so they're going to stay the course in terms of minutes and role. If he plays his way back into form, that's amazing. If he doesn't, fine - shorten up the rotation in the playoffs. In the meantime, CBS spreads the minutes around so that everyone gets comfortable playing in the event of an injury, and so that the team doesn't wear itself into the ground before the playoffs. Saying "he's garbage, don't play him" is like saying the same of Theis, or Wannamaker, or Williams, or Rozier or any number of up-and-down rotation guys.
Also, my $0.02 - this sounds like something Durant would say.