Your is a fantasy book...Well, when one considers that the iPhone 6 has the same Achilles heel as the iPhone 5 and 5S, then yes. We all know that Apple will slow down the iPhone 5 very soon, come the next major iteration of iOS, and that really there's no way that the phone cannot cope with the same o/s as the iPhone 6. It has a plenty fast enough processor to cope with any version of iOS that the iPhone 6 can. RAM is already an issue now, like it was 12 months before the iPhone 6 was even released. Come iOS9, the 6S will be out and it will have 2GB of RAM. Instantly the iPhone 6 will become compromised, and how often does that happen just 12 months after being released? Sure we expect to have a slightly slower processor and a slightly inferior camera, but never do we expect the S model to have such a major jump in crucial hardware over its predecessor. iOS9, or certainly iOS10 will take increasing advantage of the hike in RAM and all those with the iPhone 6 will be left in the same boat as iPhone 6 and 5S owners.
Apple won't slow down the iPhone 5. The iPhone 5 in the future will be slowed down by its aging hardware.
And you just demonstrated how poor knowledge of Apple's hardware you have: the jump from iPhone 5 and 5S was huge, hardware wise, because A7 architecture was really new and innovative.