Humans have recovered and prospered from far more dire circumstances, including many immigrants to the US and Europe.
You think of the '90s and the prosperity there, the end of major international rivalries, the birth of the Information Age, and imagine that time will just go on forever. Each generation is supposed to live better lives than the previous generation, right? We have the technology!
And yet the past couple of decades showed that no, income inequality and rising costs of living and the impossibility of buying housing in many markets have basically depressed American (and many other Western) youth, sort of like what's been happening in Japan all this time.
The hardscrabble Ellis Island immigrants were fleeing from clearly traumatic problems. Famine, war, disease. What afflicts modern day youth? High prices, bad numbers. It's an abstract foe with no clear solutions. It's not as if they can just move to Australia or New Zealand, another frontier of economic opportunity to start anew.
1) Anyone in school has had their education upended. Schools will be closed March through June. That is 3 months of a child or teen's educational/social/psychological development. I'm not even talking about college (which you can argue can muddle along with distance education), or summer activities (which you can argue are optional), but those have been impacted too.
2) For those in college, I would guess the majority have lost internships. Many new grads have lost their jobs. Most new grads probably didn't even get a job by March, and now they likely won't get a job until the end of the year or next year. For the majority of people who don't go to college, many work in service jobs and have been wiped out.