@gettingoldercarguy their data privacy is probably why they wouldn't be successful. The whole reason social media companies make money is because they record EVERY thing you do on the internet, package that up and then sell it to advertisers.
You exist somewhere in a database, your name isn't attached to it but you as a person are recorded. Your age range, your birthday, your likes, dislikes, who you associate with (seriously, your location data is recorded and cross referenced with you come into contact the most frequently) ect... that is all packaged up and sold to advertisers.
Here is an example: Jewelry designer wants to sell birthday bracelets, they'll buy ad space for women who's birthday is a certain month and all the "accounts" they are in contact with most frequently and ads will then be shown on those devices.