Problems related to the lack of major iOS updates may not be as important as compatible apps. I didn't expect application support to stop so soon, but over time, things like banking applications will stop receiving support when they stop releasing security updates for the operating system. It wouldn't simply be a matter of application updates no longer being compatible, but of the service (such as connecting to a service) ceasing to be compatible. Apple's decision not to support iPhone 7 and iPhone 7 Plus when iOS 16 is released later this year is proving controversial.
Owners of devices older than the iPhone 8 will need to update them if they want to benefit from the new features of iOS 16, and they are putting Apple and CEO Tim Cook to work. That's an iOS 16 feature that, for now, will only be offered on the iPhone 13, though the iPhone 14 will surely be added to the mix in September.