Well, it's dubious they are getting any marketing out of it. 10% of the schools do improve do to athletics marketing. Look at BC and Boise and many other schools. But for every BC and Boise, you can find a school that dropped sports and used the money to improve academics over the same period. The vast majority don't really get that bump. And some, as Andrew Zimbalist points out, actually get a negative impression (RU, for instance, is a fine academic school, that loses applicants because who wants to be associated with a perennial loser?). RU actually dropped precipitously in all rankings.
Finally, the donations are already counted as athletics revenues. Unless you're referring to blow-up stories like the Manziel dividend at Texas A&M (I grant you A&M is its own special place quite apart from most universities). Check out the finer details: $740 million in donations to A&M. A hefty amount. BUT, they included research grants as donations. I guess those are donations in a sense, but at the end of the day, they are won by faculty grant applications, and on the bottom line, they are included in the research budget, not the donations/endowment side.
The amount raised included 271.5m which is a huge amount, but it's geared toward the $450m renovation of Kyle Field. That's much to A&M's credit, BUT it's also an amount raised for facilities (not academic coffers). Again, it's good for A&M because they were bleeding red like Maryland for awhile, and in comparison to Texas and Michigan that relied on university funding for their $250m football stadium renovations, A&M managed to use private cash. One factor needs to be kept in mind: this money is pledged, and not raised. Given the %s of pledged versus raised, the actual number is considerably lower. Regardless, the money raised for the stadium will count as AD revenue, and not as money that goes to the academic side. The weird thing however is that it's going to be the academic side that provides the stadium funding and services the loan (assuming there's a loan).