Well he was already leaving everyone knew.
Shane Matthews was a 4th string QB who got suspended for gambling in the fall of 1989 when Spurrier was hired. Probably everyone knew he was leaving too. But he stayed for spring ball, won the job etc.
So I think the point here is that Driskel was here when McElwain was hired. Thus when McElwain was hired there were a number of QBs on the roster with eligibility remaining including a future NFL draft pick. Yet McElwain has yet to develop a QB at UF.
Could McElwain have kept Driskel at UF? I am not sure. I do know he did not keep him. Was that because it was best for Driskel to leave given the reaction of UF fans to him? Maybe, but then it was McElwain's job to sell him on staying and sell the UF fan base on him giving UF the best chance to win.
Now who knows what would have happened had Driskel stayed. Maybe UF does not win the East these last two years and McElwain is really on the hot seat. Maybe Driskel would have performed the same at UF as he had in the past and LaTech really was where he needed to be. Still none of that changes that Driskel was at UF when McElwain was hired and McElwain either did not choose to try to keep him or was unable to keep him.