I've read both of the articles linked below, and I think that the idea that we're "alone together" has a lot less to do with social media options than it does with late stage capitalism.
Disclaimer: I quit FB about a year ago and am currently trying to wean myself off of Twitter.
https://newsroom.fb.com/news/2017/12/hard-questions-is-spending-time-on-social-media-bad-for-us/
https://www.nytimes.com/2017/12/15/technology/facebook-blog-feel-bad.html