I wouldn't call it organic. The Republicans have purposefully employed a multi-decadal strategy of painting the "mainstream media" as biased and untrustworthy. This has sown excessive and mostly unwarranted _generalized_ cynicism, and granted people carte blanche to outright reject challenging facts and perspectives in favor of much more partisan narratives.
This cynicism has infected not just conservatives but most other factions. It turns out that if you repeat a narrative often enough even your opponents as well as the "mainstream media" will pick it up and run with it.
The organic parts would be the dissolution and fragmentation of the mid-century media empires--broadcast news, regional newspapers, etc--into all the various cable and Internet outlets we have today. That fragmentation means readerships are more self-selected, creating market pressures for outlets to cater to their particular readerships' preferences and biases.
This is in some sense a regression to a 250-year mean of political culture, but that's a mean of slow and highly volatile social, economic, and scientific progress.
And there's no excuse for the slash-and-burn, nihilistic tactics adopted by conservative strategists. You simply cannot have a functioning democracy unless society retains the _myth_ of an objective, shared truth. It's one thing to nurture skepticism, it's another to nurture cynicism.
Not that there's no fault on the part of the left or other political factions. But I'm not going to equivocate factions which, say, pursue ill-considered policy objectives with a faction that undermines the fundamental prerequisites for a functioning body politic.
The Donald Trump phenomenon and the age of alternative facts is principally a result of a _particular_ concerted partisan political effort. And it's not new--it goes back to before Reagan, although really got going with Newt Gingrich's Republican Revolution, which finally solidified a unified GOP narrative on all policy matters. The only difference is that we're now much more focused on some of the starker consequences of that shift in strategy.