The reason you get main-gunned is you can sit in commanders position, with a gunsight reticle to aim with - while sitting button-up.
you are basically doing all 3 essential tasks made by 2-3 people, for spotting/aiming/shooting/loading as one nervous system and from a hawk-eye position.
Try to do it with 2 people, one in gunner position with very limited FOV, and the commander sitting with or without binoculars, giving commands how to turn turret to an proximate clock position, and also give elevation in degrees- at a target moving 200-500mph, that also changes it's altitude.
I served as a tank platoon commander 79-94, we managed during all these years to get a confirmed 'kill' on slow-moving transport helicopter, using laser ranged gun sight and lead-computer at short range in an exercise.
Neither laser ranging, nor lead computers existed in WWII.