Seeing that the newest phone that doesn’t support the latest version of iOS was released in 2012, I don’t see a problem with Apple deprecating older versions of iOS.
80% of all iOS devices are on iOS 12. An additional 12% are on iOS 11. Any device that can run iOS 11 can also run iOS 12.
By not supporting older devices, you are missing out on at most 8% of the iOS population. But even some percentage of those are able to update to iOS 12.
To target anything older than the 5s means you also have to target 32 bit processors. How much time are you going to spend targeting such a small user base?
Besides, if you have an older version already in the App Store, they can download “the last compatible version”.
You'd better believe there are older devices out there, and people would use the app store with them, iff the app store would only show you apps (or versions of apps) that still run on your device.
It is frustrating trying to get games on an old iPad for the kids.
Sure they can. If there was a version of the app that was submitted that’s compatible with their device, when they try to download it, it will ask them do they want to download “the last compatible version”.
I’ve done that with my first gen iPad as late as last year to download a few streaming apps like Netflix, Hulu, and Plex.
I have the iPhone 3G somewhere in the basement. For years, it has been a paperweight, it couldn't download anything from the App Store, including apps that originally were compatible. It even lost some capabilities it originally had out of the box, for example it could not sync contacts with Google anymore.
The last compatible download feature doesn’t work on my 1st gen iPod touch running iOS 3, but it does work on my iPad running iOS 5. I’m not sure about iOS 4.
So does that mean you also support 3.5” screens? If you want to support older devices that can’t run iOS 12 but have the same screen size as a supported device then you limit support to the 5 and the poorly selling 5c.
How far down the rabbit hole do you want to go? The 4s? The 4? The 3GS? The 3G? The original iphone?