Anyone could build such applications that they might hope become the biggest in the world, but there is still a conglomeration effect. You have centralization, but anyone can become the center. This is displayed by your "biggest in the world" winner takes all perspective. For decentralization, the graph of connectivity has to not have these large communities. There would be no single Twitter (unmoderated or otherwise) that is the biggest by far.
The Italian school was foundational in this subject, so you might enjoy reading the basic material as they originally wrote it. Just be wary that it's old so the mistakes there have since been fixed.
Or he doesn't care about burnout. Because of the branding of how cool space is, and robotic missions that actually advance the science not being as sexy, he has a fresh supply of excited people (rant about the science vs the sensation). Knowing former SpaceX employees informs that.