25 or 40 years? We are talking in the world 6.5+- billion people. If a console sell 150 million this time a round, that would mean you would need 6.6 atach rate (1bil/150mil=6.6bar). I think a console can easily sell more than PS2 this gen as India, China, Russia, Pakistan, Moderate Arab States, Eastern Europe, Moderate African States, Mexico, Brazil, and the rest of the world's economies grow.
The population of the gaming market last gen was about 1.5 billion people (Mostly US, Can, Eur, Jap), this gen 80%* of the worlds population will start seeing growth in their standard of living. While I don't think that a Wii or a PS3 will be available to every Chinese National, there is a distinctive middle class growing in China.
On top of the growth in the available market, there is also growth in the market as games are being marketed to the busy lifestyles of western and Japanese gamers. (tapping into the potential of the available market)
(I figured 80% (1.5bil+1.1bil(ind)+1.3(china)+1.2bil(l.a.)/6.6bil)=77%
I would cite regulation, but I know you will simply ignore it.
