Would something like the hysteria caused by the "war of the worlds" radio broadcast be possible to reproduce today? Yeah, absolutely. The bar's a little higher though, you'd need multiple organizations corroborating the story over multiple mediums.
Enough people on twitter would say things like "Uh, I'm standing around where the aliens are supposed to be and I don't see shit" to arrest some of the contagion.
I have a theory that new modes of communication automatically seem more trustworthy at first, because most of the time the liars don't move in until adoption reaches a certain level to make it profitable. The problem is that transition. We're late in the cycle right now for the internet. People are slowly learning to take extraordinary claims on the internet less seriously by default.
I like to think about the impact of Franklin D. Roosevelt's fireside chats. Most of America tuned in, captivated. The things he said calmed people down, reduced national anxiety and assuaged their fears. The default mode was to trust him, and that made a historic impact. It felt nationally like the president could finally talk to people on a personal level.
Then a few years passed, and the national trust was taken advantage of. Despite Tuskegee, MKUltra, The Bay of Pigs, Watergate -- pretty much everything about Nixon, and a hundred other events, it took a long time to make the majority of us into the politically disillusioned wrecks we've become.
It's easy to imagine how seductive messages like "the elite are all lying to you" are when that's become the safest default position for a while. The vulnerability we've found ourselves in now is lies bolted on to truths. I'm hoping that we'll all inoculate ourselves with some kind of generalized agenda aversion next.
A man running for state representative came to my door a few weeks ago. He wanted to know if he could place a sign in my yard. To be honest, my default position would have been to say "Go for it homie". Any candidate making door calls is atleast trying to put in effort. Especially since political candidates basically spout vague platitudes that turn into nebulous nonsense.
Fortunately for me, he seemed adamant he wanted to show me the key thesis in his pamphlet before I made my decision, he opened it up and tapped on the header. "Muslims are a problem for America."
"Ohhh you're a racist!" I said politely. "Thanks for letting me know, I have literally no interest in that being in my yard. Have a nice day!"
We don't even have symbols for the bugs in our brain that allow history to repeat itself like it does.