It's a case of balance in my opinion. My DS is 12 and could easily spend his entire free time on his Xbox. Although sociable, it doesn't seem healthy to me to do only one thing with your free time, whatever it is.
He'll generally have 2 days in the week where he's on the Xbox from when he gets home until he goes to bed (3:30-9:30). He'll be on WhatsApp and phone calls during that time too. Then an average of 3 hours per day every other day.
For balance: 2 days a week he has activities/clubs after school, and may not go on the Xbox at all.
He's out with friends or at sleepovers frequently, and we have family time or outings in a normal week too.
He spends around 10 hours a week drawing and working on art pieces, and probably a similar amount on reading.
I would happily replace some of the screen hours with more time spent doing physical activities, for balance, but he hates all sports! I've tried to push him into taking one up, and he chose sword fighting, so that left me a bit stuck. Yes, I did suggest fencing. No, he wasn't keen.