I think that's kind of the point. We, as adults, use e-mail, especially at work. By the time these teens get to work, what will happen is a mix of 1) They adapt to using email 2) They'll use their way of communicating with their then-colleagues.

New technologies are adopted more slowly at work, but eventually they will be, because people will use what is efficient for them. (For a good recent example, look at the adoption of wikis in companies)