That's a good point but I think McElwain's response to that incident was part of the problem.
Didn't he sort of push Grier out of the program? He could have stayed in Gainesville, served his suspension and come back the next year or after that. But, the scuttlebutt at the time was McElwain either didn't like Grier (and/or his family) or thought he was a good enough coach he didn't need a QB like that. I think Grier was a Muschamp recruit and McElwain might have held it against him too.
Whatever happened, if he had stayed in Gainesville things could have been really different. Treon Harris as the worst Gator QB in memory and I'm an old guy...