This is not clear at all. The blog author is simply asserting it without providing any supporting evidence.
http://en.wikipedia.org/wiki/PlayStation_Portable http://en.wikipedia.org/wiki/Nintendo_DS http://en.wikipedia.org/wiki/IPhone
http://arstechnica.com/news.ars/post/20081114-october-npd-sa...
The PSP has always been a bit of a dud.
It seems you submit every entry from your blog, and IMHO there's nothing wrong with that, but you have to admit it, you rarely get votes. Maybe it would be more successful if you change a bit your strategy looking for higher quality posts with more information and analysis and less opinion, in less posts.
http://news.ycombinator.com/submitted?id=kimboslice
My $.02
The iPhone is not killing portable gaming devices. My God, look at Monster Hunter in Japan. It's a lack of good software.