Because they use colleges as their minor leagues and farm teams for free. Free!!!
Baseball and hockey have to train and nurture future players that aren't quite ready for the bigs. That cost a tremendous amount of money and there is no way around it. Even though the expenses of day to day operations are much smaller it is a major expense never the less.
Colleges however foot the bill for the NFL and the NBA. Football is the main revenue producer with basketball second best. Baseball and hockey are funded by football money for the most part.
Sad to say, higher education is not about learning and future income producing jobs, it's about who is number one!
Yes, I followed that logic for many years.
But we often wondered when the student athletes had time to study, sadly many did not. The dream of the big time money paycheck was missed by most of the players. It was only an illusion.
TV money supplies the rest. The networks fight tooth and nail for the rights to broadcast sports. Everyone makes money on the deal except the players.
Someday it will end. Football is facing its biggest scare with head injuries, parents are not letting their kids play. Hockey and baseball are finding it harder to find good players. Basketball and soccer will continue to thrive because all you need are two nets and a ball.
It won't all change in my lifetime, but change it will.