However, that is not going to happen for many of them, as the new version of the operating system will likely be too heavy to run on them. People who want to benefit from iOS 9 to the fullest will have to invest in new hardware, while this is not the way the system works with other mobile platforms.
Could the trend for Apple change in the future? It’s entirely possible that the company will finally realize the need for future proofing and start to make their devices more powerful even if their current operating system can’t benefit from that hardware yet.
This style of hardware design drew some criticism in the past when the iPad Air 2 came out, but as we’re seeing right now, it can be a move with actual merit if it’s done right. Hopefully, Apple know what they’re doing and they have a solid plan for their future devices, because the company can definitely benefit from making some releases that last longer on the market.