Guitar Hero III breaks 5 million

Guitar Hero 3 is quickly overtaking the records that its predecessors set, with over 5 million copies being sold between all platforms. Activision have stated that Guitar Hero 3 has managed to outdo its predecessor, Guitar Hero 2, by selling almost four times the amount of units sold for GH 2 in the same amount of time. One must take this into account though: GH 2 was released on the PS2 and the Xbox 360, whereas Guitar Hero 3 was released on at least 5 platforms. Is it simply the popularity of the franchise that is boosting sales or the fact it’s been released on several more platforms? Source: Wiiz