@ naznatips
I disagree with you when you say
"Not a single one of the companies benefits by moving to a new generation, and none of them will for at least 3 more years"
Sony benefits a lot by launching a new PSP in 2011 Spring, since PSP software sales are tanking and so is hardware sales.
And if Sony releases a new portable, the DS will feel even more dated.
Based on Nintendo success with DS, they don't need to rush, but because of Sony they will put a new portable on the market late 2011 or spring 2012.