Either that, or centralization will reassert itself brutally and force a new consensus.
This type of consensus did exist, and could be reached, in the 1770s, long before centralized mass media. The creation of competing "chains of trust", which see an election as legitimate or illegitimate, a virus as dangerous or fabricated, is actually only possible by the manipulation of mass media. And social media very much is mass media. It's just a version in which propaganda is funneled through the mouths of its target audience.
Even in the constitutional era, there were constant questions with foundational implications. Is slavery moral? Should Native Americans be forced to move wherever the government finds convenient? Can states secede if they don't like the election results? These were all active disputes at the time, with competing "chains of trust" on both sides.
Getting out of this was a century of real and cultural warfare that ultimately resulted in some of the first rights of countries, because forcing the centralization at the point of a gun was just not worth it.
Mass media is a much more recent, much more short term and much less powerful (there never was a newspaper czar and Walter Duranty could at most destroy your career, not burn you at the stake for telling the truth).
My point is that humans have had different groups with different values living inside the same countries for a long time before they considered themselves to be members of that nation, this is going back to what was normal, not reverting to something that is new.
Of course living with these separate groups wasn't exactly peaceful or without discrimination.