Never.
In first half of this year Wii gained only 600k compared to PS3+X360. And to gain 50% marketshare it need to catch up another 5 milion.
And second half year probably won't be as good as first half. Shortages will hurt Wii sales and it won't be able to grow as much as PS/360 during Holiday.
First half of 2007 Wii won with HD consoles by around 1 milion units. But in second half it lost by 300k.