Agreed, iPhone 4S and other is no longer supported on iOS 10 due to aging hardware, 5-years lifecycle is not bad for a new replacement and Apple need to push better hardware and I believe FPGA will have the biggest role for mobile secure mechanism, AI and VR/AR in mobile device. Psst, you know Apple and Acron cofounded ARM? I'm one of the users who love futuristic technology and there are lot of crazy inventions could be feasible.
The same for Android and some are still using vulnerable versions. It can be free if the OS does run auto update, if it cause data loss, it will cause headache. I feel Windows updates is already making our IT jobs miserable. There is nothing to stop anyone from trying paid subscription mobile OS, if it's successful and gather strong community support, you will see it on HackerNews #1 rank. ShowHN.