While I understand your point and don't disagree, let's remember Fitz was signed as a back-up and security blanket for Geno. The fact Geno was "the guy" actually supports your point better than Fitz's presence.
Good point when he was first brought on board in 2015. I think in 2016 he was earmarked the starter from day one.
He knows that too and if he got anything it would be as a backup and he probably has no interest in being a backup again. I see him retiring and with his education he will be just fine.