I think you're saying that mass broadcasting is going away? If so, I believe that's true in a technological sense - we don't watch TV or read newspapers as much as before.

And that certainly means niches can flourish, the dream of the 90s.

But I think mass broadcasting is still available, if you can pay for it - troll armies, bots, ads etc. It's just much much harder to recognize and regulate.

(Why that matters to me I guess) Here in the UK with a first past the post electoral system, ideological coherence isn't necessary to turn niche opinion into state power - we're now looking at 25 percent being a winning vote share for a far-right party.