When Bowden took over at FSU they were unranked and weren't very good his first year. The next three years he had a 2-headed QB system and they ended those three seasons ranked 14th in the AP, then unranked but went 8-3, then finished 6th in the AP. So your "ZERO programs" is inaccurate. FSU was built that way. However, I think that is an exception rather than a rule AND Bowden did not set out to run a 2-qb system. It just worked out that way and Bowden was smart enough to use his guys in a way that helped build them into a powerhouse. As soon as those two guys were gone he went to a single starting QB situation.
As for GT I think this fear of building our program with a round-robin QB system is just something else to argue about. Patenaude's history doesn't show he wants to do that and the times he has are when nobody has shown they can consistently get the job done and he rotates them until someone does stand out and then he goes with that guy. At Temple his first year they had nobody step up and lead at that position and neither Logan Marchi nor Frank Nutile stepped up and set the world on fire. I don't think either of them did enough to be thought of as even starting a small campfire. In the second year it didn't take long for Anthony Russo to establish himself as the single starter. Arguably last year we had even a worse QB situation than Patenaude inherited at Temple and this year, while I think we have clearly more talent at the position, we have very little experience (even Graham isn't super experienced). Even at Coastal Carolina he very clearly stuck with a single QB system. So history says that if one guy takes the reins then Patenaude will stick with him.
BTW don't mistake this for me being a fan of Dave Patenaude. I'm not. He has not won me over. I was concerned about his hiring and I still am. But more because of his lack of D1 experience, not because of the system he runs and certainly not because of any fear that he would run a round robin QB system.