Some don't come anywhere near Bright Hall. Advertisers have target audiences. Next, closing the Owl's Nest early means students must find food elsewhere. This could include the Dining Center. Many people may not know, but the Dining Center is not just for dorm students.
Any student can go in, pay the required fee, and eat until satisfied.
You could also look at bottom line reasons. These would include less staffing needed, less food required and other cost cutting measures. All of this sounds nice. But there are holes in the story. First, the selection of food at the cart lacks.