Well it all depends on this holiday I guess. It's not safe to do such doom predictions anymore since holidays last year on the USA.
In my humble opinion, Wii is following the GBA path having very strong early years and then suddenly dropping out of the spotlights. In a grander scale, of course, but it has no impending successor as an excuse. Looking how things are happening right now, the same is happening to the DS (in it's own scale, mind you) so maybe is just the way Nintendo platforms behave nowadays.
By the way, this generation is way more balanced already. It is not hard to compare and see:
Worldwide hardware 31st July 2004 -
| PS2 | 212,627 | (-14%) | 69,924,823 |
| XB | 77,611 | ( 1%) | 15,477,692 |
| GC | 51,029 | (-2%) |
15,075,239 |
Worldwide hardware 31st July 2010 -
| X360 | 195,120 | (-12%) | 41,710,061 |
| PS3 | 151,976 | ( 24%) | 36,327,839 |
| Wii | 149,898 | (-0%) | 73,027,003 |







