First, to quote the article:
> The big gainer, interestingly, is under the same roof as Facebook. It's their co-owned Instagram
Now, to my point: The average person does not care about privacy, just the illusion of privacy (I suspect people reading this site intuitively know this. At some level, nearly everyone is in different ways, it turns out.)
Instagram provides that illusion by not injecting opinionated content into your feed (The most obvious example: you aren't seeing injected news stories in your Instagram feed, generally its only ads and people you follow, and the ads are marked)
Rest assured, they're getting their data's worth, maybe not the same way, but photos (particularly metadata on the photos that most smart phones, for instance, default collect) are just as (if not more so) valuable, not to mention there are still a myriad of other ways of collecting privacy intrusive data about users.
Hows about that?
(just to show my assertion is not completely unfounded, check out this survey:
https://www.pewinternet.org/2015/05/20/americans-views-about...
The survey says: 9 out of ten americans care deeply about privacy (particuarly around data privacy and collection)
Yet, our actions, even faced with the outright knowledge of those very things being actively and routinely violated by services, is not enough for people to leave platforms for good, simply, people shift between social media outlets, like those leaving Facebook over privacy concerns yet still continue to use Instagram, in fact, Instagram is projected to grow as noted in this article, in part because of people migrating away from Facebook)