Of the seven OL Robert noted, three transferred to FCS schools, three transferred to exactly nowhere, and one moved to the DL.
I think everyone else looked at these guys and saw the same thing Bret did: They were not now nor would they be in the future FBS caliber OL, let alone P5 talent. A series of missed evals by the prior staff.
None of that's a guarantee that the guys Bret recruited will be. If you know you have a problem it's better to start searching for a solution sooner rather than later.