I mean, I'm a reasonably successful young(ish) professional earning not far off £100k and, having built a number of PCs in my life and by and large owned top end Android phones am also pretty tech savvy, but I'm strongly considering the SE as my next phone. I want to step away from Google, partly because I'm starting to value stability and simplicity over an all singing all dancing experience, and partly because their stance on data concerns me. And there is nothing the higher end iPhones do over and above the SE that I need. Sure, they look nicer and I'll be taking a step back from a bezel-less display to big bezels, but the 11 is too big for my use case, and the 11 Pro is way more expensive and, while I could afford it, I don't need to.
My point is that the SE hits a really good mark in the market, and is not just a phone for poor, image conscious people