The abuse of autoritative source (not to be confused with “authoritarian”) positions for personal upside maximization (which often meant spreading propaganda) and subsequent fall in trust in authoritative sources long predates Trump.

I mean, in the US, Newspapers - which are supposed to inform people, not to convince them of anything - openly gloat about their “opinion making” and are criticized if they do not openly support a candidate in Presidential Elections (the very opposite of Journalism)

Then there’s the decades-long massive abuse of “expert sources” on Finance and Economics by Neoliberalism to push very specific narratives, for very specific political ends which overwhelmingly benefited a very specific subset of people.

What you’re seeing now is the product of the deceit practiced by many of those who are supposed to be independent experts who inform the rest on important subject, and the blanked distrust on the the Media and “experts” and subsequent blooming of shameless loudmouth liars who speak with maximum confidence in politics is really just the harvesting that which has been sowed since at least the 80s.

IMHO the tipping point was decades ago and what you see now is the acceleration downhill having been going for long enough that the speed of travel downwards has become scary.