Having read the whole book, I am now convinced that this omission is not because Srinivasan has a secret plan that the public would object to. The omission, rather, is because Balaji just isn't bright enough to notice.

That's basically the entire problem in a nutshell. We've seen what people will fill that void with and it's "okay but I have power here now and I dare you to tell me I don't" and you know who happens to have lots of power? That's right, it's Balaji's billionaire bros! But this isn't a sinister plan to take over society - that would at least entail some amount of doing what states are for.

Ed:

"Who is really powerful? The billionaire philanthropist, or the journalist who attacks him over his tweets?"

I'm not going to bother looking up which essay or what terrible point it was in service to, but Scooter Skeeter of all people made a much better version of this argument by acknowledging that the other axis of power wasn't "can make someone feel bad through mean tweets" but was instead "can inflict grievous personal violence on the aged billionaires who pay them for protection". I can buy some of these guys actually shooting someone, but the majority of these wannabe digital lordlings are going to end up following one of the many Roman Emperors of the 3rd century and get killed and replaced by their Praetorians.