Good question! I often wonder this myself. I have to young teens that live next door and I never see them out ever. Even in Summer. Their parents have come over and went swimming and I asked them where their kids were? Playing video games. Maybe I'm just old but I was always outside playing baseball or doing something outside. I guess in the electronic age, the kids just want to play video games instead of playing outside. I guess it's an addiction with kids nowadays! Not all, but most. They should be enjoying the great outdoors!
I think that it's was a concept that is fairly novel at first but now it's like that's what developers focus on too much and as a result of the now mass populous purchasing more and more consoles many often yearn to play with other gamers or people who are in contact with them.
This increases more demand in online gameplay as they might feel the gameplay is more exciting due to the surge of other human players instead of AI