I have been thinking about this for some time now. There is no doubt this happens. My moms iPhone 11 is on iOS 26 and over the last 2 OS updates, its reached that exact point where it is 'glitching' like the twitter video says. Now that it won't get a new update this year it seems it requires an upgrade, not from new features, but from the existing ones no longer functioning efficiently.

My theory is that the 'malware' is simply heavier updates on older phones that don't really need it. For example the camera app in iOS26 could be significantly slower than in iOS 15 for example. It may do a few extra things but it could do them just as well on the older code base. Now with the new code base, the exact same feature runs slower on an old phone but runs the same on a newer phone with a relative difference noticeable.

This is probably because Apple hardware team is far ahead of the software team. There is a lot of headroom, and instead of doing something innovative with it, apple choses to instead just bloat it to sell more phones.

Apple with this strategy becomes the most environmentally unhealthy company. Of course we need a way to prove this.

What I would do is get an iPhone 12 with iOS 14 to iOS 27 and compare how fluid and snappy the UI is. its probably hard to get an iPhone with iOS 14 because apple cleverly doesnt sign it.