As I mentioned in post 25, that note is about macOS, no explicit mention of that requirement for iOS.
Before the big picture with the iPhone Software Update menu is this text:
“Users can also decide to update or upgrade their devices when a new major operating system is available.”
At the moment, there is no recommendation to upgrade on iOS 15’s page
About iOS 15 Updates
https://support.apple.com/en-us/HT212788
About iOS 16 Updates
https://support.apple.com/en-us/HT213407
More, as the image provided by
@FeliApple shows, iOS 15.7.1 is still being offered to some devices as the main option.