You don't think there will ever be big black-centric black-owned social media, correct? Not being antagonistic, just curious what makes you say that?
In the video, you see that these companies started because of restrictions. It's safe to say that these companies would have sank if they allowed foreign competition early in the game.
Also, it's possible to be a big black-owned social media company, but not Black-Centric. To go back to the video, their success wasn't based on being Chinese, there was service gap that needed to be filled.
Being black-centric may work in an majority black country because it's the default their. But not over here, to put it nicely there's no leverage.