I think a part of the Internet's appeal to some is the ability to post their opinion without personal judgement on the character. You can voice an opinion or ask a question quickly and mostly anonymously.
We have been used to text with newspapers and the digital world for a really long time and it's certainly not going away.
A good example of this is forums. I don't imagine forums being turned into video clips of you responding to replies. It's just too personal and involved (my hair has to be nice, have to be clothed, and can't be shoveling in ice cream while I talk).
Now that's not to say that there can't be an increase in video usage. But I don't ever see it becoming a main source of the general internet public's way to create content.