This is the essence of college football fandom. The strong tie is the match between the diploma on the wall and the name on the front of the jersey. For many, it started in High School. You knew the guys personally, had classes with them, hung out with them etc. This continues to a lesser degree in college, as college football players are more separated from other students. Colleg football players still take classes and personally interact with the other students. While in school, there may be only one degree of separation between you and football players.
Anecdote: on of my suite mates would regularly shag for a scholarship FB player who was last string tight end. He wanted to work on his other skill, punting, more than he was able to during regular practices. This was how he chose to use his personal time. An NFL team was glad he did.
Once that connection is made, you watch your school, then add on schools your team plays regularly, and schools your spouse, friends, neighbors etc follow. Thus you have millions of fans in hundreds of stadia watching college football. And millions more fans watching it on TV.
Once that connection is broken, then the audience will drft away, if the "college" football players become only minor league professionals.