"That's just mad. $700 worth of iPhone in 2007 is worth the same as $700 of iPhone 6 in 2015? Adjusted only for the general inflation rate over those years and not for the improvement in performance? Whut?"
Apple (it's manufacturers) have continued to improve the design, manufacturing and distribution costs over the years. I am pretty sure I have read somewhere (can't remember and can't be bothered to look for the article) that Apple have reduced the whole design, build, distribute process cost in half from what it once was. So they are factoring in the increased performance of the hardware in the price, they have just reduced the costs to themselves massively.
So whilst people are saying "wow look at what you can get for the same money as 8 years ago" they really should be saying "hey Apple, you pay so much less now, where the fucks our discount"...