Overall this generation is going to be around for a bit longer than people may think.
The last thing people want to think about at the moment is upgrading to the new 720/PS4/WiiHD in the next few years when there are so may people still not upgrading from the PS2 yet.
IMHO, the Wii is a totally different kettle of fish, there is a huge audience of people wanting a Wii that would not have traditionally bought into the games market, so you can't realistically include Wii sales numbers as lost PS2 > PS3/360 upgrades. It is a games machine that is totally casual in comparison to the 360/PS3.
We have yet to see a huge number of PS2 owners upgrading to either the 360 or PS3 and TBH, this is what will make this generation (with respect to the 360 and PS3) last that little bit longer.
Also, even although the PS3 is last at the moment, it is currently passed original Xbox number already and is starting to pick up steam down to the better games library and more attractive pricing.
I honestly can't see a PS4 (unless PS3 sales effectively stop over the next 1-2 years) until at least late 2012 / early 2013.
It will need a serious 6/7 years on the market.
Prediction (June 12th 2017)
Permanent pricedrop for both PS4 Slim and PS4 Pro in October.
PS4 Slim $249 (October 2017)
PS4 Pro $349 (October 2017)







