I think it's social media, that's what's really changed: Every single teenager is now comparing themselves against every other kid in the world instead of just their local peers (and maybe a few grainy MTV stars over 525 scan lines). And of course the "popular" ones they're comparing to are the most successful, most good-looking, most privileged i.e. the most "perfect" ones (because that's how they got to be the most popular). It's a terrible yardstick for anyone to measure themselves against, let along impressionable young minds.