ANswer: because of Brand of psOne and PS2.
both consoles had best games, so and ps3 will have best and exclusive game in this generation.
moreover, after this spring ps3 will get better and better multiplatform games, with better graphics compared to xbox360. 
Every 5 seconds on earth one child dies from hunger...
2009.04.30 - PS3 will OUTSELL x360 atleast by the middle of 2010. Japan+Europe > NA.
Gran Turismo 3 - 1,06 mln. in 3 weeks with around 4 mln. PS2 on the launch.
Gran Turismo 4 - 1,16 mln. with 18 mln. PS2 on the launch.
Final Fantasy X - around 2 mln. with 5 mln. PS2 on the launch.
Final Fantasy X-2 - 2.4 mln. with 12 mln. PS2 on the launch.
1.8 mln. PS3 today(2008.01.17) in Japan. Now(2009.04.30) 3.16 mln. PS3 were sold in Japan.
PS3 will reach 4 mln. in Japan by the end of 2009 with average weekly sales 25k.
PS3 may reach 5 mln. in Japan by the end of 2009 with average weekly sales 50k.
PS2 2001 vs PS3 2008 sales numbers =) + New games released in Japan by 2009 that passed 100k so far
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