Here's the practical consequence that settles it: in boxing, you can't take the fight to the floor or stall your way out of a bad matchup. You stand there for up to 12 rounds while brain trauma accumulates. MMA has more ways to win, sure, but that's variety, not toughness. The other side will say you have to defend everything in MMA. Fine, but boxing forces you to keep defending the one thing that ends careers while your legs go and your corner can't save you. MMA tougher? No. Boxing just doesn't let you hide.