Up until recently mobile devices had been getting ludicrously massive performance gains year over year, much like traditional PC's had before ~2012. Going from my iPhone 6 Plus to iPhone 7 Plus two years ago was an absolutely massive leap in terms of even day-to-day performance, meanwhile outside PC gaming I'd have a hard time justifying a replacement or upgrade of a mid-range or better laptop or desktop made in the past 6 years.

Times have changed however, had my iPhone 7 Plus not died on me I wouldn't have bothered to upgrade to an iPhone XS (I had an extended warranty through T-Mobile and got the device swapped just to trade it in for a $300 credit) - it was still stupidly fast and I certainly wasn't missing any of the gimmicks in the newer devices. This is probably why T-Mobile is now testing 3 year financing options with the iPhone XS and Galaxy Note 9.