It will all depend on not just hardware but also software sales.
One thing is for sure though: We will not see a new home console and portable console both in the same year. What does that mean? Well we're likely to see a PSP2 and DS2 either in 2010 or 2011. That means that Sony and Nintendo are looking at a window between 2011 and 2014 to release their next gen console. I've always thought that 2012 would be the sweet spot..
Now think about Nintendo's position here:
DS software and hardware sales will likely begin to drop next year if they don't this year. This will be offset by ever increasing Wii sales in both the software and hardware departments.
In 2010/2011 Wii will most likely be hitting its peak in software sales and definately hit or past its peak in hardware sales. Therefore for Nintendo to continue to sell the amount of software and hardware it has been and to continue its growth, they'll need to have a successor to DS out in late 2010/early 2011.
Now if that's the case, they want to allow time for that console to grow in sales and slowly offset the aging DS. It won't be able to offset the slowing Wii however and you'll see price drops and colours and bundles to keep sales from dropping too quickly, lucky for Nintendo they have PLENTY of breathing room. Then we'll likely see an unveiling and release of the Wii2 in late 2012. Wii will continue to sell as the DS is dying and their new console begins to blossom and the new cycle will begin.
Sony again are in a similar position and are quite clearly trying to squeeze as much life out of the PSP as possible. This is most likely due to the fact that they're trying to expand their audience just as the PS2 did in the late stages of its life. It also means the PSP will probably have a price drop this year to drive sales and get some momentum happening for its successor.
I see a similar time period for the release of the PSP2 as the DS2, in 2010/early 2011.. However by now the PS3 will have had a price drop or 2 and so console sales should be healthy and software sales will probably be around 1 or 2 higher than it is now which isn't ideal. If the PSP2 really does well from the start then Sony can hold off a little bit longer on releasing the PS4 as it'll cover the near dead PSP and sluggish PS3 but if not then expect to see a PS4 in 2011/early 2012.
Microsoft don't have a portable to cover their asses but they do have a console with a very high attach rate and room to move price wise. The most important thing for them to do now is to expand their library and continue to lower the price to really expand into the late casual adopters. For Microsoft though, it's likely that the 360 will see a decline next year if not this year in software sales and then in hardware sales. In fact it's almost certain they'll see a decline next year. I think when they see that happening, we'll start hearing about the 720 and it'll probably be released in 2011 to get the jump on the others.
So my predictions are:
PSP2 2010 Q4
DS2 2011 Q1
XBOX 720 2011 Q4?
PS4 2012 Q4
Wii2 2012 Q4
That seems a lot like this gen :P hmm maybe it'll turn out a bit different... I don't know how though... Sales seem to point to those dates..
We'll see I guess won't we..
