The question was, can the OnePlus 5T rival the iPhone X? The only real measure of being a rival is sales.
I think it's quite clear a lot of people buy phones because of the two things, yes. It's why Apple puts out the best ads, and why Samsung pours so much into good advertisement as well. It's the very reason Samsung took the opportunity to bash the iPhone in ads a few years back, because people react to that kind of stuff. The talk about Apple for the past several years is how they are behind on tech, so are people really buying because of the tech? The general consumers, not tech nerds or MacRumors posters, largely buy iPhone because it is an iPhone. I'm a big iPhone fan and have carried one for the last ten years, but they win with their marketing and hype, and not because they have the latest tech, and there is nothing wrong with that.
You aren't all of a sudden going to find a bunch of people carrying a OnePlus 5T because it is a OnePlus or a 5T. There is a very narrow niche market for that device that will not rival the iPhone.