They threw in the academic advantage as an afterthought, but it makes a lot of sense from that point of view. Who pays for the dorms and meals when freshmen come in the summer before they start?
At the end they mentioned the recruiting/summer league part, which would also have to change quite dramatically, with more emphasis on fall events, and that's not so good for the high school student-athletes.
As far as attendance, in a college town of a D1 that I'm familiar with, the college baseball is popular, but once the high school and little league seasons start, attending games becomes harder because the kids who are most interested are playing their own games. We went to a lot of early spring games, when the weather was decent. There's not a huge audience of just random baseball fans, that I can see, and they would lose the audience of their own students, not that that ever seemed very big.