I've always thought it has, but I have begun questoning this recently.
According to NPD, 19% of Ps2 owners in USA also own a Wii. This is roughly 8M. That means there are only 3.4M Wii owners who didn't own a Ps2.
There are sold roughly 25M GC + XB in USA, and a little more than 40M Ps2s. This means that by the same rate, more than the amount of Wiis would have been sold.
So a lower upgrade rate from GC + XB to Wii than from Ps2 would be needed. As a matter of fact, and about equal rate from GC, and a low rate from XB would still lead to only ~ 500K new purchasers.
So am I missing something? Or...?
http://www.vgchartz.com/forum/post.php?id=1128743