My son is indoors most of the day in the summer. There are two differences, that I see, from when I was a kid. First, it's hotter than hell here in Utah. It's above 100 every day. That just sucks for outdoor stuff. The other thing is air conditioning. When I was growing up (Englewood), if you wanted to stay cool, you waved a piece of tree bark in front of your face. We didn't have fancy shmancy air conditioning. So, there was really no good reason to stay indoors.
The video game thing is a big deal, though. Growing up, there were only so many hours you could play Pong without wanting to stick a salad fork in your eye. Now, nearly every kid has multiple gaming systems, and dozens of games.
And then there's that blasted rock and roll music, which is all about sex and worshiping Satan. But I digress.