You're assuming the person even bought the console\PC, or that person has literally ever had more then 20$ in their hands at once. Managing your own money is one thing, managing someone elses is another thing entirely.
Gaming is a thing of entertainment, and it gives you entertainment nothing else can. Sure, you could just stare at a wall without ANY socialization for your entire life, but you would literally just eventually go into a mentally disabled state with no socialization. Just like for gaming, you could just not game for your entire life, but you'd miss out on a lot in life, a lot of inside jokes or references to events that happen in games, trends and soforth that would make your social life in general degraded.