It really is dependent on an individual. These 2019 phones will come with a lot more capabilities as is often the case, because they will have next generation A-series SoC with next generation NPU, enabling them to do more on-device processing for photos/videos and security.
I also don’t think there is going to be a problem on the real devices. The dummies that are circulating the internet always lack the sparkle the real devices have. I’ve noticed this every year. The truth is that, the average person keep their phone for at least two years, looking at how much more processing the Xs have above the X, the XI or whatever it will called, should be technically quite a step up for an iPhone 8/X owner, let alone iPhone 7 or 6+ owners.