this was pointed out by someone so, i will repeat it here. the odds are in florida's favor except for.....
here are recent national champions that returned their starting qb.
nebraska '94. repeated as champ.
tennessee '98. can't remember what bowl they went to in '99.
fsu '99. national title game in '00.
miami '01. national title game in '02.
usc '03 (split). repeated as champ.
usc '04. national title game.
florida '08?....
you can see that 5 of 6 on that list played for all the marbles again the following season (but, only two of them won).
i don't know how much of the other talent returned the following season for those other teams.
tennessee had the worst season (sorry, to bring that up) of those on the list and if memroy serves.....they still had a very good year in 1999.