I saw the article on wattsupwiththat and there was a direct correlation with new iphones and slowed older phones for every iphone release. It is not the battery, Too regular and too correlated with the new phones.
If it were the battery then they are really bad engineers to design such a shortfall. Interesting that all the android phones do not suffer this battery issue. Must be better engineers.
Lesson? Turn off your iphone updates before every new iphone release- or go android, which is what I did.