The NCAA and the ADs along with the highly paid, uber-powerful HCs would never allow the early sign date to be that early and run the risk of having LOIs in place and then have rash of injuries that affects your FB Program
I'm sure GT wouldn't want to have 20 LOIs from your hypothetical signing date and then have 8 of them suffer season ending injuries during their Sr. season, and be stuck with them
This is still a business, and you want your raw materials to arrive in as good a shape as can be expected
Before you get all holier-than-thou, there's gonna be a downside to CFB, it's always gonna be there, better to manage it than complain about it