I'm old enough to remember Atari when it was new. Playing a video game at home was quite something, no quarters required! But it also had somewhat limited replayability. Doesn't matter how good you are, eventually Defender is going to beat you.

The NES was a radical departure in how games were played and how good they were. You'd never spend all day in front of the Atari, but you could with the NES.

Add to that the steady increase in the availability and affordability of cable tv, then VCRs and video rentals, and now the TV is even more central to the ordinary person's life. Then came computers, the Internet, etc.

I think there is definitely something to kids just not being as interested in going outside. Why would they be? All their friends are in the magic box in their pocket. Outside is where you get sunburn and ticks that make you allergic to meat.