I don't know anything about Florida but my guess would be you are correct and that state would swing according to the relative success of FSU and Florida. But I live in South Carolina and have watched SC Clemson games in many parts of the state at sports bars. The ratio of fans is between 70-80% USC over Clemson at the sports bars which is consistent with what people keep telling me when I do my informal survey of how the state trends.
What is unique about the 20-30% fans in SC that support Clemson is that they are every bit as passionate as the majority of fans supporting the USC teams. They don't have any sense of inferiority and, by their stadium numbers, back up their passion by placing people in the seats.
My uneducated understanding of the support ratio being what it is has less to do about success than about the cultural attitude and demographics of the state. USC is perceived by the average South Carolinian as the every man's university. Clemson is perceive as being more elite. And SC is still in a rebellious cultural attitude towards anything elite and the GDP in the state is in the last percentile of the U.S.
In another post I felt the ACC had the markets of NC, Virginia, Md and Fl if the ACC teams in Florida did better than the SEC team. The rest of the markets were SEC. Three and one half states does not make a case for developing an ACC network especially since the most important 1/2, Florida, is whimsical. And this is why many of us in this forum are relating to you and @bstimpy the mistakes Swofford and the ACC have made by not taking UConn and Rutgers. The ACC could have ultimately, if RU, UConn and BC improve a modicum in football and do some of the things I pointed out in the other post, get NJ, most of the populous areas of NY, and NE. I would have added RU and UConn first and then considered Syracuse to shore up NY.
But the ACC wet for the s e xy short term fix instead of the smarter long term fix.