is because DJ is not really the main problem. In fact, I'd argue that:
1) Playcalling/Scheme
2) Personnel
3) Run blocking
are all bigger problems. Can someone ask Norvell why Morlock, Courtney, and West all play over our two 5* freshman TE's? Can someone ask Norvell why he doesn't take more big shots? Can someone ask why Williamson, Williams, Holmes, etc. take reps away from Douglas, H. Williams, Toafili, Davis, Poitier, etc.? Can someone ask Norvell why Armella, Otto, and Simmons haven't ever been given a series, much less a fair shot to play, when the guys in front of them are terrible?
I have no problem believing that Glenn would be worse, if put in the same spot as DJ. DJ has a bigger, more accurate arm, is poised and at the very least, isn't turning the ball over at any quicker of a rate than he did in his last 4 years of CFB (~1 int every 40 attempts). He obviously can't read a defense and needs a full game of scripted plays, but the inability to adapt to the personnel and inability to put the most firepower on the field at all times, is a much more glaring reflection of Norvell than it is of DJ. If Norvell thought he was getting anything other than what we've seen, that is also a much more glaring indictment of Norvell.
Most teams would give their left *$& to have H. Williams, Poitier, Douglas, Benson and Brown out wide with Toafili and Davis in the backfield. Can't remember the last time I saw us run the ball outside the tackles, attempt to impose our will in the running game with our 6'4 250 lb+ QB (whenever the run it, it works), keep a TE and a RB into block in the pass game, run a quick slant with Williams or Benson, bring in a lead blocker on a non-goal line play, run some misdirection until the defense is forced to respect it. All I see is the same tired offensive scheme, with the same guys who haven't gotten it done, despite being given extensive opportunities to do so. Go back and watch the first series of the GT game, there is plenty of talent to have a viable offense, but it might take some creativity and ability to adapt to your personnel. That's on the HC/OC, not the QB who everyone is trying to make the scapegoat.
FWIW I don't think DJ is very good, I just happen to believe that Glenn is worse (lots of people forgetting how bad he looked in his two starts last year) and they don't want to ruin Luke K. behind this OL. You can't convince me, that we can't have a halfway decent offense, even with DJ at QB.