I don't understand the 'who could he have brought on' argument that points out, correctly, that everyone on the bench probably wouldn't be better than who they'd replace. It's a logical argument in a way but isn't it usually the case players on the bench aren't an improvement on players selected ahead of them on the pitch, hence why they're on the bench in the first place?
Surely substitutions have other considerations and benefits such as helping players avoid fatigue and injury or even exacerbating existing injuries and knocks further?