Speaking as someone who is still very new at the whole leaf tea thing, I think there is a lot of interesting commentary in this topic.
Tea, in the US, seems to be regarded as stuffy and uptight. Generation after generation of coffee experience has made coffee very embedded in the culture. It is hard to break that.
The genius of Starbucks is that they took this very common thing and showed that it could be better tasting. Their genius was to target the growing part of the market that wanted to go to something much better. This is the same market that wants to get a BMW, Mercedes, Lexus, or Audi. The same that wants Gucci or Luis Vuitton. Starbucks started out with these people and grew from there.
I see lots of teens buying Starbucks now, but I don't think too many people could argue that this segment was the original target market. The whole spread of Starbucks was from an up-market segment towards the general public. You know you've hit the masses when you have shops inside Target. (Target seems to be marketing themselves as premium lately, so it isn't an odd combination.)
But, back to tea. The big question is how to spread the love of quality tea to a wider audience. While I think this will happen slowly over time, there are a number of hurdles that will slow down this.
Firstly, as I mentioned above, tea doesn't have the same level of integration in the US society as coffee. This makes tea much more foreign. We don't have huge commercials for tea like there have been for coffee in years past. The recent healthy living movement has helped a lot to improve the visibility of tea, however.
Secondly, tea isn't a good fit with tastes in the US. Those in the US can attest that we like our stuff highly seasoned and flavored. Tea is quite weak in taste compared to other drinks, and certainly isn't anywhere near as sweet as some of those "coffee" drinks you can buy. With dulled senses, it can be harder to appreciate the complexities in taste.
Thirdly, there seems to be no good marketing strategy developed yet. It seems that there has been no hit on a good niche market to start building a strong base on for expansion. However with the healthy living movement and more of the public looking for premium stuff, seeing Lipton advertising pyramid bags is a good thing. It shows there is a market for better-quality tea, and also shows the public that there is more to tea than those familiar bags.
On that third point, there is a chain over where I am (and I think they are national) called The Coffee Bean and Tea Leaf. They do both coffee drinks (like Starbucks) and whole leaf tea. The stores have a nice atmosphere, and I've seen college students on several occasions studying there and consuming some kind of drink. (The fire pit most of their stores have outside is a nice touch.) Honestly, I got my first loose-leaf tea from them when I decided to try expanding my tastes.
So, how do you get teens into tea? Go after the older folks first who are looking for premium tastes and then work your way down to the teens. Give the fast-paced society here a convenient way to enjoy good tea fast (places like CB&TL are doing a good job here) and they might just get interesting into how to do it themselves.
Sorry if I rambled.