I lived there for 5+ years and am a graduate of the U. My personal experience is what I'm using. Miami does not have much following in Florida outside Miami-Dade, and inside Miami-Dade it is weaker than Pitt's following in Allegheny County. Give the two programs equal records, and Pitt is outdrawing Miami fairly easily. And I make that assessment based on what I saw, and I was there when they won their last national championship when they were giving out tickets for free to fill to try to fill the Orange Bowl.
If I am the SEC, which seems most interested in large brands that can fill large stadiums, I'm taking FSU over Miami every time. Miami is not like an SEC school at all, where FSU is. In fact, I can see UCF surpassing the U in Florida, if they haven't already. Here's the reality. In South Florida, particularly in Miami, no one cares about college sports. Heck, they barely care about sports at all. It is a very transient area where athletics is not really on the forefront of what people are engaging in. It flat out is a terrible sports town. The sports fans there are people from the northeast or elsewhere, and they largely keep their loyalties from whence they came.
What the U is living off of its glory days and has is a national brand for people that get caught up in the swag image, and it draws national eyeballs on tv, but within Florida, the U pales in comparison to UF and FSU as far as fanbase. The Big Ten is more about markets so the U would be more likely a school that the Big Ten could be interested in for the media market, although it doesn't really go for smallish private schools.