Lol, you do know that a 20,000 seat arena does not seat 20,000 for a concert typically, correct? Maybe "in the round".
20,000 means at capacity for standard events with all seats.
Typically most shows do not sell tix for behind the stage.
So the remaining seats are 14,000 capacity for a 19,000 seat arena, probably 15,000 capacity for a 20,000 seat arena.
Not barely half full...seriously man, you ok? I cant present the facts any clearer for you except to literally pull all the data for concert capacity.
I showed you one venue's stats...they are all the same man.
over 80% full on average...some more some less. So that would be substantially more than half. Just so we don't get more confused, half would be 50%.
So 80% is more than 50%.