Many also got jacked up on psychotropic drugs from childhood thanks to their boomer parents. Remember that shit rolls downhill, if they're having a shitty time it's probably because something got dumped on them, one way or another. Decades of wage stagnation, COL increases, and declining job prospects haven't made for a particularly generous offering for up-and-comers, and some can't cope as well as others.
Now, that's not entirely an excuse, as there's a certain measure of bootstrapness that should come with being a grown-ass-adult, but sometimes the cards are stacked enough against you that if you don't have a particular personality or haven't been shown proper coping skills, you might fall apart.