Does 20 count as young? I just don't have the time to devote to laying music at the moment - too busy trying to get my bachelors! But most of my friends listen to folk, as well as rap, goth, rave, rock, metal, country, etc.
I think that's the difference, maybe? Many of us listen to a lit of different genres so it's not as apparent that we're folkies, too. But if you go to Appel Farm or the Potomac Celtic Festival, then you'll see plenty of little ones and teens and twenty-somethings wandering around. Myself included.
There was a great group of young 20s aged people here in VA called Roaring Mary, but then they got a little older and started getting jobs in other parts of the state/nation and so they no longer exist. They were gooood, tho.