Young people (and really any working age people) just really don't have that much time, energy, and (mostly importantly) money to dedicate to impacting election and legislative results. When you're working age you have more imminent things to worry about, but the matter of fact is that it's mostly retired people who think the world is going to s*t whose voices are heard the loudest.

Of course you can say it's a question of priorities and it's "their fault" for not being politically active, but I would argue the system is stacked against young people's political participation.

Also, most places in the US have minimum age limits for elected positions.