Can't compare an iPhone to a car. One drives you and takes you to work or leisure, the other does nothing but take calls and play media/apps.
I think it's still a useful comparison though, because this is a thread about whether or not the iPhone X provides enough value to justify the price, or do people regret it? The same question can be asked of whether or not someone regrets buying an expensive car, or if they'd be just as happy with a less expensive model. Most people would say they need a car and a smartphone. They provide different services. Most people would probably say they could do without the smartphone (or even a basic mobile phone) more easily than they could do without a car, but that's not going to be true for everyone. I spent 10 years in a city where I didn't need a car, and even now I barely drive the one my wife and I share. Fortunately I live close enough to work to bike or even walk. The only time I ever drive a car is on evenings or weekends to do grocery shopping or take a trip for leisure. I can get through the day without my iPhone as well, but my day will definitely go more easily and be more enjoyable with my iPhone. I use it to stream podcasts, news, or music on my walk to and from work. I use it for personal communication (voice, text, etc.) and work communication (Slack, Skype for Business, Outlook, ticket tracking system). I usually take a number of photos per day. I also wear an Apple Watch and use it along with my iPhone for fitness tracking, task and project management, calendar, reminders, etc. The iPhone helps me be more productive, efficient, and healthy. Yes a less expensive model could do all those things too, but that's not really the point. It's the value we get out of the $1,000 bucks is the point. I use my iPhone for many things, so I probably get more use and more value out of it than someone who uses it only for voice calls, texts, and occasional web browsing or driving directions. My wife has no interest in spending $1,000 on an iPhone X, or $350 on an Apple Watch, because she just wouldn't use them as much as I do. The value just isn't there for her.
Likewise there is little value to me in owning a nice car. For me the car is just a way to haul more groceries home than I can fit on my bicycle. A nice luxury car would be wasted on me, but a nice iPhone definitely is not wasted on me. I also like nice bicycles. Fortunately it costs a lot less to own a luxury iPhone and a luxury bicycle than it costs to own a luxury car.