I would say that given the fact that the 360 has pulled away by a further 2 million over the past few months you would expect this trend to continue for at least the first quarter of 09. I would think that realistically Sony will be doing well if they can sell on par with the 360 next year my honest opinion is that Sony would have done okay if they are remain sitting 8 million behind the 360 at the end of next year.
I think enough time has passed to show that the PS3 wont ever start selling like hotcakes, the 360 has nearly reached mainstream prices and once they reach there and get established the system will continue to sell well. Everyone waited for the XBox 1 to overtake the PS2 in sales and it just never happened and I think the same will happen with the 360 and the PS3 people are waiting for a sales spike that wont ever occur.
As for the talk of when xxx game comes out, that will cause a small spike here and there, but seriously if it was about quality software being released then the WII wouldnt be sitting where it currently is.
I think if Sony can get their price down they could sell on par with the 360 so minimum lead would be around 7-8 million while maximum would be 12-13, my honest opinion will be around a 10 million lead at the end of 09.
