Say this gen lasts for 4 more years, or to make it easy, 200 weeks.
Ps3 + X360 combined currently has a lead of 6,18
That means that Wii has to average 30.9k over 360 + Ps3 combined, if it shall make 50%
If it was to last for 150 weeks more, the Wii would have to average 41,2K over Ps3 + X360.
From 1.1.2008 untill now, Wii has sold 3.883M
From 1.1.2008 untill now, Ps3 has sold 2.549M
From 1.1.2008 untill now, X360 has sold 1.875M
From 1.1.2008 untill now, Ps3 + X360 has sold 4.424M
Ps3 + X360 has sold 541K more than Wii so far this year. That equals about 36K each week.
Ok, from week ending 2nd february untill now:
PS3: 1.712M
X360: 1.270
Wii: 2.607M
Difference: PS3 + X360 = + 375K more than Wii
Difference pr week: Ps3 + X360 has sold about 28K more than Wii each week.
360+Ps3 average this year: 294K
Head start: 6180K.
For Wii to achieve 50% market share this year, it will need to sell 167K more than Ps3 + X360 each week.
If Wii sells 1M more than Ps3 + X360 during holiday season, it will still need to sell 139K/week more untill holiday season starts, that is about 430K/week or 1830K/month.