Why is Steak 'n Shake so popular in the east coast?

I don't get it. I live in central florida, and I've been to several steak 'n shakes. Every one of them had mediocre to bad service. The waiters/waitresses wouldn't seat you for like 5 minutes or more even when there are booths/tables open. They are too busy running around like chickens with their heads cut off. I know they can be busy, but its so unorganized. It's like they don't know what they're doing. And they are such a pigsty at times, with messy booths/tables not cleaned yet. Don't get me started on their food, because their burgers are ok, nothing amazing. The shakes are the only thing going for them, because the fries suck :(