The iPhone is a very mature product. It does essentially everything a cell phone needs to do, and does it to near perfection. You can say the same for other phones from Samsung and other manufacturers. There have been mostly small incremental improvements over the years, with a few significant innovations like wireless charging, face and fingerprint recognition, smart watches and CarPlay/Android Auto, but they will be few. The 15 is an incrementally better phone in most ways. I’m not sure these people even know what exactly they are looking for from Apple.
That my take on it. I am retired and have a half a dozen third party apps. The only reason I bought a 13 Pro is for the bigger screen. It does make a difference trying to read stuff, especially FR. You can run a small business from an Iphone or Android phones..