You're wrong because you're ignoring two things. Holiday sales boost is very big and the PS3 has had 3 exclusives released on it so far in the US in total.
In the next 5 months, it's getting like 13 or so exclusives so games + holidays will boost sales.
Add to that the price cut (even if it is temporary which I don't think it will be) and you got yourself a PS3 that should easily reach 7-8 million worldwide if not more by the end of this year.
Next year definitely looks to be a bigger year for the PS3 with more price cutting and two huge franchises coming in the form of FF XIII and MGS 4. Also, Killzone is going to be pushed by Sony a lot and if it turns out as good as is hoped then that will be a big seller as well, specifically in the US.
Thanks to Blacksaber for the sig!
