The benefit of having the band on the Thanksgiving Day parade from a marketing standpoint is immeasurable though. That's a lot of eyes who saw USC who otherwise probably wouldn't have given USC another thought. The Carolina Band is traveling to London next summer as well. That's huge from a university public relations standpoint.
I don't think we're at the point yet where schools will get rid of bands. It's too much a part of the culture, pageantry, and gameday tradition. Remember the outrage when the Citrus Bowl told Iowa their band couldn't perform at halftime a couple years ago? The backlash was so strong the bowl game changed the ruling and allowed both Iowa and Tennessee to perform at halftime.
Sure, college bands across the board don't play as much today as they once did, but that's a long way from getting rid of them entirely.