From 1974 through 1994, the teen employment landscape changed very little. Around 40 percent of teenagers had a job during the school year, surging to 50 to 55 percent during the summer months. But in the past 20 years, teen employment has plummeted during all seasons:
Summer jobs are for white people
An even more intriguing finding in the same Pew Research Center is that there are huge racial disparities in teen employment patterns, with the summer surge in youth employment basically not existing at all for black and Hispanic teens:
Teens don't want jobs anymore
It is tempting to attribute this to deep shifts in the fundamental structure of the American economy, but one important factor here seems to be that the kids these days don't want to work. Consider this chart Challenger/Gray made out of Labor Department data:
This shows that the increase in the number of teens who aren't in the labor force is driven entirely by an increase in the number of teens who don't want a job.
Work is less appealing when non-work isn't shameful
Pew doesn't provide a comprehensive theory of why this is happening, but Ezra Klein's look at the future of work gets at part of the story.
While unemployment reduces income, unemployment is considered shameful. The unemployed become happier when they retire, even when there's no change in their material circumstances.
By the same token, the decline in youth employment is probably self-reenforcing. If you're a teenager and few of your peers work, neither they nor your parents or teachers will regard your unemployment as uniquely problematic. And that sharply reduces the personal incentive to work. It used to be that it was common for teens to work during the school year and they were expected to work during the summertime. Now it is uncommon to work, which on its own makes work less desirable.