I've said this in another thread, but American youths just don't vote, unlike older folks. This is not a recent phenomenon, this goes all the way back if you look at voter turnout records stretching back from the 1960s.

Young Americans from across generations love to complain but don't do anything. In other countries, the youths are more energised and proactive. You'd notice their politicians are much younger, manifesting the youthful proactivity. American politicians are older on average, because older folks vote more, and voters prefer someone who is their peers whether they realise it or not.