Yes, the Wii is competing with the 360 and PS3, and it's easy to prove it

[libellule]

Very good point NJ5,

I believe people dont see these sales strong evidence because they keep looking the line-up or the market targeted : the sales show the Wii is making dammage to the PS360 but a part of the last-gen owners are still going to buy a PS360 and no Wii.
That is why, I think, Wii is competting versus PS360 but a lot less than the PS2 with the GC/Xbox/DC because the market has been divided by Ninty aiming the casual/familly market since day1.