I think part of it is software upgrades, many of which are optimized for newer hardware, or not optimized for out of production hardware. So when new features are added/enhanced older systems may see a slowdown, another factor is newer hardware runs faster so some new updates may not care about optimizing as it runs fine on the newer system anyways.
Have used Apple products for a while, they don't really like spending a lot of undue effort on stuff they don't sell anymore.
Still running iOS 8 on an iPhone 5s, works great, I hear newer iOSs are not as efficient on this phone, so will stick with 8 on it.
No it is my opinion but a reasonable conclusion to come to.
--> Battery wear is a measure of device age, or a good proxy for that in most cases. --> Apple wants people to keep upgrading their hardware --> primary reason to upgrade is old, slow device --> Apple ensures devices get slow as they get older.
If it was really Apple acting in the users interests, then it would be a user option, not a secret setting in the code.
"Apple ensures devices get slow as they get older" Do you have a statistic for that or is that anecdotal?
I'm perfectly happy with my 5 year old iphone. I notice the Facebook/Skype/Slack app get larger and larger over time. https://sensortower.com/blog/ios-app-size-growth Primary reason to upgrade for me is lack of security updates, Apple stopped supporting the iphone 5 (any 32bit CPU device) for example.
I’ve heard people claim better device performance after resetting to factory settings. Maybe this is just a case of needing to clean out the crud and not downgrading based on battery?
Have used Apple products for a while, they don't really like spending a lot of undue effort on stuff they don't sell anymore.
Still running iOS 8 on an iPhone 5s, works great, I hear newer iOSs are not as efficient on this phone, so will stick with 8 on it.