Apple's design inconsistent?

9to5mac reader Alex B. sends in this illustration detailing the differences between different design elements in Apple’s products UI.   I guess the thinking is that if Apple’s aiming to move all of its platforms into one consistant UI, the elements should look the same across applications and platforms. 

I’m wondering if these differences are on purpose to give each application and platform its own feel.  When you see blue in the interface your brain goes into portable iPhone mode.  When you see different scroll bars on the side of an application window, you know instantly what application you are in.  If they were identical, you’d have a hard time differentiating them.

My brain took a big hit when Firefox’s windows started looking like Safari’s a few years ago.  From then on its been an annoying bit of extra work to figure out which application I am in.