KingKold on 19 February 2010
The main thing to consider here is when the Next Gen actually begins, see.
Assuming it happens after 3 years, then the OPs prediction could very well hold true.
"best selling console...by the end of this gen"
But as everyone else pointed out, the Wii is NOT gonna stop selling at the end of this gen, and as a result could/may still end up being the best selling console of all time (which may not happen at the end of this gen, but proceeds until the next gen).
So you see the key words in the OP is "...by the end of this gen"
There is no Knowledge that is not Power
