Yes Magic,
because those statistics count schools, families who don't use their PC for things other than work, and grandmothers.
Anyone who put the money in for a gaming PC, the ones who would even TRY playing these games, would aim for Dx10.
You are correct with that however lots of gamers are kids therefor its not up to them if they upgrade or not, it's up to their parents/legal guardians and considering the way the economy has been for the last few years i can honestly tell you they had other things on their minds then "Better upgrade my child's computer"