I think that, in part, the article is misleading since I did not take away that Facebook thinks there's no purpose to text or that it will vanish entirely, and likely they share the same opinion as you.
The counterpart line to the "text is dead" idea is the following from Facebook in the article:
>“The best way to tell stories in this world, where so much information is coming at us, actually is video,” Mendelsohn said. “It conveys so much more information in a much quicker period. So actually the trend helps us to digest much more information.”
To me, this says less about "text is dead" and more "our users are choosing to share experiences with video, and they're doing it off-platform." Similarly, they continue with the following:
>"But Mendelsohn went further, suggesting that stats showed the written word becoming all but obsolete, replaced by moving images and speech."
I think 'text is dead' is Facebook's segue to bloviate about an upcoming set of features surrounding multimedia, which in turn is pretty much just a "stop uploading videos elsewhere" gambit. Facebook does do a pretty good job at making videos uploaded elsewhere work seamlessly with Facebook. I'd have to imagine that the next natural step is just to get those on Facebook in the first place.
So, I don't get the impression they want youtube-cut videos to replace the textual Facebook arguments; I think they're just trying to build up hype for FacebookVid or whatever they decided to call their next set of multimedia features.