This is an interesting point of view, especially because it generates a lot of contention.
I’ve seen it a lot. I have repeatedly stated throughout various conversations with people who have told me that me saying that “you claim it’s fine because you eventually forget how it ran on its original iOS version” is rather disrespectful.
Performance is difficult to measure. The only objective aspect is keyboard lag, which practically always happens. Interestingly, perhaps people don’t care enough so as to notice, but for somebody who is used to running original iOS versions, it’s the first thing that comes to mind. But performance issues can be denied and I have no way of proving otherwise. I can give my own experience but they can just claim that it doesn’t happen to them. People typically claim it’s fine, and any issues they have are almost always justified with the RAM being too low or the processor being too slow, factor which is never true on an original iOS version barring specific cases like the iPad 3.
Battery life, if provided with sufficient information, however, is an easy one to ascertain. A screenshot with enough SOT and enough information and context provided, is all I need if I know the device’s original version battery life to estimate a pretty accurate battery life loss.
As a user who presumably used the iPhone 13 Mini on iOS 15 for a little while, it’s easier to notice. Another interesting aspect is that the degradation with people who update through every little version isn’t catastrophic, but constant, barring some horrible major version like iOS 7 on the iPhone 4. So in my view, and like you said, the person periodically gets used to this being a little slower. Or this other aspect like the keyboard being a little laggier. And then it’s a little laggier than before. And a little slower. But I do think that it isn’t the same. I am using an iPhone 6s on iOS 13, and the keyboard is significantly laggy, performance significantly slower, battery life abhorrent. I’d call it usable in terms of performance, but why do I say that it’s absolutely abhorrent in reality? Because next to it I have an iPhone 6s on iOS 10. Because I’ve used the iOS 13 one for a few months... and the iPhone 6s on iOS 9 and 10 for a whopping (and continuous) 8 years. I know every intricacy of perfect, original versions for that device. Which means I’ll notice any and all shortcomings. I want to clarify one thing: it’s not a matter of any superiority. I’m not more sensitive or more perceptive than anyone. But they haven’t used iOS 9 and 10 for almost 8 years. You’re bound to notice less, especially when the end of a device’s lifespan comes and you’ve seen massive degradation cut up in smaller chunks throughout the years. To give an example, I haven’t used an iPod Touch 4G on iOS 4 for 13 years. I have one on iOS 5. It’s decent on iOS 5... but do I remember how it worked on iOS 4 with extreme detail? I don’t. Can I say that battery life and/or performance was worse? No. But do I know enough to affirm that iOS 5 is just as good as iOS 4? Also, no. So I don’t do it. That’s the only part I criticize (well, I don’t do it because the iPod Touch 4G hasn’t been relevant for a million years, but that’s another thing entirely).
Other companies are reinvesting almost everything they make. Apple is too focused on marketing and creating an image (which of course also includes the outside material of the Macs or iPhones and things like that, everything contributes to the image).
