Fun fact: did you know that no other starting quarterback is profiled less on TV while on the sidelines than Mike Glennon? It's true!
So...that's weird. It's not like the Bucs have dominated time of possession and not allowed any room for quarterbacks to be shown on the sidelines. It's not like there's been no reason to cut to Mike Glennon after successful or unsuccessful drives.
Maybe it's because he looks like (a giraffe/Napoleon Dynamite/insert-favorite-comparison). Maybe it's because the Bucs have lost a lot of games. Maybe it's because he doesn't show exasperated facial expressions on the sideline. Then again, maybe he does and we just don't know because TV directors never show them.
I don't know. I genuinely can't think of a reason why. I just know it's weird.