^Way before the NES and way before the PC was a viable gaming platform there were plenty of hardcore gamers in the arcades, on the 8-bit home computers and on the older consoles. I was there, and there were young kids my age pouring coin after coin in arcade machines and talking about the best strategies while they walked to school. Buying magazines that detailed the games of the Atari VCS down to the last score for each kind of ship you shooted down, giving strategies and revealing exploitable glitches. It doesn't take long for a small child to become infatuated with something. Believe me, we were no less hardcore in our interest than any modern gamer can be. And since consoles and computers were much rarer, it was way more likely that an owner was a very dedicated gamer, not a casual one.
About the households, assuming it means what it sounds like i.e the share of the hosueholds that have bought a given console, the two things are not mutually exclusive. The number of households where a console is bought can decline while inside those households there is more gaming performed by casual adult gamers and in family reunions and less by younger kids on their own.
Again, just like Reasonable I am european and the PS1 around here was the apparent threshold that liberated gaming -or at least some gaming- from the geeky and kiddy image.
