honestly its a bit tough for either xbox or ps3 to hit 100 million. in the past 5 years the console sold 65m, which is amazing but it still has 35 million to go and just probably one holiday season when it is the "current" generation console on the market from playstation. lets say by the end of the year it sells another 10 million then it will be at 75 million. 25m to go. and the ps4 and xbox 780 or what ever its called will be around the corner. i think the ps3 would have a good 2013 from the line up it has (beyond two souls, god of war, the last of us) so i think it can sell another 8-10 million that year that would leave it for about 15 - 17 m to go, which is a bit tough with next gen consoles released. depends on emerging markets and the price tag it reaches. if it reaches 100 $ it is considered a good deal for a blueray player with a good library of games. and we still have to see the effect of the PSN on old gen consoles, maybe indie games will help keep them alive for more than we thought possible?
