Because its better to roll over the majority of the value of the 6 into the 6s then roll that over into the 7. If I can get $500 for this unlocked iPhone 6 128GB then my final cost for the 6s will be $240 after the Discover Promo. I Next year I sell the 6s and get the 7.I was trying out the force touch shyt on the 6s at the apple store. It's handy but why are folk with a 6 buying the 6s? I'm thinking about copping a 6 which is cheap right now....and grabbing the 7 when it drops next year.