My guess is they want to combine all the small spaces into a single larger one, which makes more sense for the way modern retail /restaurant economics works. They can likely afford to wait out for a top tier tenant because of the billboard revenue.Take down the billboard, open the windows along Lake, and you'd have yourself a handsome building.
Even though it's great to see Lyn-Lake becoming a nicer entertainment destination, I mourn all the quick service restaurants we've lost -- they're good assets for this kind of neighborhood.