I think something really unexpected would have to happen to stop the ds before it reaches 100 million units, because sony can't really believe into a victory anymore and the best games for the ds are yet to come.
however, it will be interesting from a marketing point of view how the next nintendo handheld will be called. i think the brand name gameboy is at least as well known as playstation and it would be quite stupid just not to use it anymore. but on the other hand, ds is becoming a brand name too... i really wonder how nintendo will carry on. maybe they will try to do what they planned intentionally and make the ds their third leg. this would mean that they release a new gameboy which is as powerful as the psp while they still support the ds. probably this scenario is not realistic but it would be a possibility for nintendo to ensure that they keep dominating the handheld market, because if this new gameboy would fail, they could just abandon it and concentrate onto the ds 2.
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