Maybe the liked the sign the way it was? Maybe they liked the 5 Points identity being displayed on their marquee? And like @mtrain pointed out, maybe changing that part of the sign is not in their budget/cost-prohibitive. If I remember correctly they do have signage on the doors and box office that display the Sun-Ray logo and name. And honestly, until I saw the photos I never really noticed that part of the marquee anyway.
I just wanted to point out the correct name so that the writer could update it (thank you, by the way) so when people not familiar with the area stumble across the article and think "Hey, that looks like a cool theater" they Google the right thing.