Based on my data point of one teen in the house: yes, if by "Skype" you mean the IM end of it, and SMS messaging via phone probably compensates for the paid voice calls the phone companies are not getting.

Teens don't really do voice much unless SMS and IM bandwidth is too low, like planning when I'm going to drive her around (and even then she'll put in her original request in SMS). I've asked her about it - if you're doing voice, you're restricted to talking to only one person at a time.

Although my 11-year-old tends to do confcalls (one memorable night at Cub Scouts he was confcalling with friends in St. Louis and Puerto Rico... the world is so strange sometimes); I think at his age text input is just too slow.

I don't like articles of the form "The <X> Is Dead" because they're always hyperbole - voice is still the highest-bandwidth information transfer beyond actually being face to face, and that isn't going to change for a long time. Like other communication channels, it's merely being augmented by others, but not replaced.

  > voice is still the highest-bandwidth information transfer
  > beyond actually being face to face

Unless you're including 'video calls' in 'being face to face,' I would put those at the highest-bandwidth information transfer.