Your argument seems feasible on the surface, but when you did deeper you uncover two flaws. First, there is no tv money for FCS or G5 football. ESPN might offer FCS a token payment to play in the spring just as they give the MAC to play on weeknights in the fall. But that would not amount to much. Furthermore, every "created for television" spring professional football league has failed. And the regional sports networks turn to their cash cow, MLB, seven days a week starting in the spring.
Second, although television money has forced baseball to play until it nearly snows and basketball to crown a champion in June, on the basic level American sports are deeply rooted in our culture and strongly tied to the seasons. Football in the fall. Baseball in the spring and summer. Basketball in the winter. For baseball and football that pattern has been set since the 19th century.