I think Wii will win the generation, but some of factors Stickball mentioned prevent me from thinking Wii will have over 40% when this set of consoles stops selling. Still, Japan already has high HD adoption and that is Wii's best region, which is why I think Wii will still sell the most overall. In the West, I think HD adoption will favor PS3 and 360 among gamers who want cheap, traditional game play and pretty graphics. So in 2009 or 2010 I can see PS3 or 360 selling alot. But, even if 360 is say..$199 or $250 by then, I think alot of people will keep picking up Wii if it is $100 or $150. PS3 will pick up on 360 in Europe and Japan, and when it costs less than $400 for the good model, it will move ahead of 360 worldwide (this I think happens in 2010). Considering 165 million consoles sold last generation, I'm not really predicting a tie in raw data, just close to one in percentages. If the market goes to 200 million this generation (through 2014, with the vast majority of sales through 2012), then it would be:
Wii - 76 million
PS3 - 66 million
360 - 58 million
Not what I would call a tie. SNES and Genesis were 23% apart in marketshare and the difference was only 19 million, but with a bigger market, a smaller percentage can mean similar seperation in units sold.
You're probably wondering how the hell Sony will get to that many...well here is how I see the years going
LTD (yearly sales)
2005 360 - .7 LTD
2006 360 - 8.5 million LTD (7.8 million), Wii - 3.19 million LTD, PS3 - 1.25 million LTD
2007 Wii - 18 million LTD (14.81 million), 360 14.5 million LTD (6 million), PS3 8.75 million LTD (7.5 million)
2008 Wii - 36 million - (18 million), 360 - 25.5 million (11 million), PS3 21 million (12.25 million)
2009 Wii - 53 million (17 million), 360 - 37.5 million (12 million), PS3 36 million (15 million)
2010 Wii - 65 million (12 million), 360 - 46.5 million (9 million), PS3 49 million (13 million)
2011 Wii - 71 million (6 million), 360 - 51.5 million (5 million), PS3 58 million (9 million)
2012 Wii - 74 million (3 million), 360 - 55 million (3.5 million), PS3 63 million (5 million)
2013 Wii - 75.5 million (1.5 million), 360 - 57.25 million (2.25 million), PS3 65.5 million (2.5 million)
2014 Wii - 76 million (.5 million), 360 - 58 million (.75 million), PS3 - 66 million (.5 million)
My rule of thumb is..9,000,000 hardware/year is the bench mark for great sales. That works out to an average of 250,000 units/territory/month.
Sales/Grade/Description
13.5 million+/year A - Console in full swing (375,000 sold/territory/month)
9 million/year B - Console revving up or down (250,000 sold/territory/month)
6 million/year C - Average sales (166,666 sold/territory/month)
3 million/year D - Console dying/launching slowly (83,333 sold/territory/month)
1.5 million/year or less F - Console Dead/very supply constrained launch (41,666 sold/territory/month)
Looking at it like that then...
2005 - 360 - F
2006 - 360 - B-/C+, Wii - D, PS3 - F
2007 - Wii - A, PS3 B-/C+, 360 - C
2008 - Wii - A+, PS3 A-, 360 B+
2009 - Wii - A+, PS3 A, 360 A-
2010 - PS3 - A, Wii A-/B+, 360 B
2011 - PS3 - B, Wii C, 360 C-
2012 - PS3 - C-, 360 D, Wii D
2013 - PS3 - D, 360 D-, Wii F
2014 - Wii, PS3, 360 - F
Wii lifespan (throw out F's) 2006-2012
360 lifespan (throw out F's) 2006-2013
PS3 lifespan (throw out F's) 2007-2013
Look at it like this too:
10% Total sales reached...
Wii: May 2007?
PS3: October 2007?
360: Sept 2006?
25% Total sales reached...
Wii: Jan/February 2008
PS3: October 2008
360: December 2007
50% Total sales reached...
Wii: Jan/Feb 2009
PS3: October 2009
360: April 2009
66% Total sales reached...
Wii: December 2009
PS3: August 2010
360: Feb/March 2010
75% Total sales reached...
Wii: June 2010
PS3: January 2011
360 August 2010
90% Total sales reached...
Wii: October/November 2011
PS3: March 2012
360: March 2012