This is about as likely to be correct as the predictions of those a few years ago saying that Nintendo would dominate for multiple generations on the back of Wii's success.
If Microsoft does things exactly right, then the Nextbox could definitely win the next gen, with or without Japan's help. It only needs to win over continental Europe. I think it's not likely to win over continental Europe, but it's a possibility.
Wii U can still pick itself up. So Nintendo should not be counted out.
Upshot is it's not possible to accurately predict which console will be the top seller based on current information. So for the most part it's wishful thinking.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix