this would affect all of college athletics especially with regards to title IX. Because it would then just break away from college all together.
But the flaw in your logic is that College Football is not percieved as a semi pro league. it is college athletics. If it turns into a semi pro league, the popularity of football will wane. People will be less likely to be connected to a semi pro league than they to a college team. Americans don't care about minor league anything.