An honest iPhone 8 launch event would say "we improved the camera hardware but also had some fantastic breakthroughs in the camera software, and we'll be backporting those to all supported models in iOS 11". The pessimist in me says that nobody would buy an iPhone 8 if they did this. Wait a second, now that I've thought it through it's obvious that this is exactly why they didn't backport the software improvements to previous iPhones. :)