Does Apple deliberately slow its old models before a new release?

I really wish I could revert my iPhone 4s to iOS 6. On ios9 things are really slow. Especially Facebook, but it's hard to say whose fault that is.

I know you're probably thinking "Dailymail, ew" and "Betteridge's Law", but the evidence presented is fairly damning. It shows that people seem to collectively notice a slowdown in their apple phones when a new one comes out, and the effect is not there with the natural control group (people that own samsung phones). This implies that Apple does indeed sabotage their older models with software updates.