SF's point was the most accurate when it comes to this issue.
UM has always been a dichotomy/split between the "local" fans, and "alumni" a small part of which is local, but many of which are scattered all over the country and the world.
As SF said, in the 80s, UM was like having a second pro team in Miami. If you grew up in Miami in the late 70s and 80s, you had the Dolphins, and the Canes. That was IT. FSU rather s*cked until the early to mid 80s when they chased our coattails into relevance. But as SF said, Schnelly helped save UM football by selling it to the city/community. He got South Florida to "buy in" to "Suntan U" and it became "our team". And when UM became a national power, it drew a ton of new fans in, who prior to that, really only had UF in the State of Florida and FSU to a lesser extent to follow as "big time" programs go.
One thing people forget, is that there are probably a LOT more UF and FSU alumni in SoFla than there are UM alumni. That's just the nature of the beast. Those are the big state schools, and UM is a very expensive smaller private school. Not a whole lot of people in South Florida can afford tuition at UM. ****, of all my friends growing up who stayed and went to school in Florida, ALL die hard Canes fans, maybe 10% ended up at UM. The vast majority went to UF, FSU, UCF, FIU, etc. The reality is, UM does not have a deep alumni base in South Florida, its just not big enough. So without the support of local non alumni, you see the kinds of crowds you have seen the last few years. Pathetic empty stadiums, becuase when the team is losing, and now that its all the F*CK up at JRS, the casual local fans have been bleeding off for the last decade. Many of them have also come to have divided allegiances. I worked with a dude a few years ago, who grew up in the Palm Beach area, and was a die hard Canes fan as a kid, went to games, etc.. But when it came time to go to college, he ended up at UCF. Being a UCF alum, and having a Division I football team, he is now more of a UCF fan, and still sort of roots for the Canes, but as more of an afterthought. Its like that for a LOT of people.
And now that you have FIU in town too, as much of a joke as they are NOW, they are still bleeding support away from UM, as there are now TWO local Division teams in Miami Dade, and even though FIU is still somewhat of a commuter school without a national rep, the people that go there, and the alumni, of which there are MANY more than UM, do get a sense of pride that they have their own team now, and its helping to put the school on the map. NOT to mention that they actually PLAY closer to the city than JRS does. So many of those "casual" local/non alumni UM fans of the 80s, and 90s, have now been pulled in other directions, and there is not enough of an alumni base in So Fla to carry by themselves. This doesnt EVEN factor in all the Pro sports teams now in the area, which werent here in the early 80s when the UM brand built up... (Marlins, Heat, Panthers)
Lets face it, when you compare apples to apples, UM's DEEP fanbase is probably closer to that of Boston College, Tulane, or Pitt, than it is FSU, UF, Bama or ND. The only difference is that UM is in a metropolitan area, like Pitt or BC, and we have had a great deal of success, which has created many fans in South Florida, and around the country. BUt many of those fans, are fans we made in the 80s, and around the millenium. This is a program that if it doesnt win, it doesnt fill the seats. It never has.