I've said this before, having followed the conspiracy stuff for a long time (got into JFK stuff before the Stone movie). There's always been a group of people who bought into conspiracy theories, and it seemed like early on many were pretty "damaged" in some way - a lot of the early JFK conspiracy believers were personally vested in the mythos of JFK in some way or another (America would have turned out better/life would have turned out better if JFK had lived). The UFO folks, yeah, many needed their own baggage terminal to follow them around. And there were some who just needed excitement in their lives and conspiracy theories made them feel special and "in the know".
Up through the 90s, their reach extended to a small section at bookstore if they were lucky (my first exposure to the JFK stuff was to Garrison's book at a B. Dalton in the 80s) buried with the astrology stuff. Their reach outside of somebody seeing one of the few "mainstream" books was normally the backrooms of independent bookstores and student unions, found by flyers tacked up on telephone poles or bulletin boards in said bookstores or student unions, as well as physical mailing lists (which were expensive at the time unless your followers were paying you). They were mocked/ridiculed by normal society and the media. There was a barrier to entry if you wanted to peddle theories/scam people. It was hard to reach a significant number of your fellow conspiracy theorists unless you really worked at it by way of snail mail mailing lists.
Fast-forward to the mid/late-2000s and the barrier entry is down to almost nothing - email lists and websites were easy to create. Search engines put your stuff out there. There was the potential for a lot of mini-Art Bells to crop up. And then YouTube ramped it up. All of the sudden "normal" people could be exposed to this stuff, and some took the bait. Jump ahead 10 years and some of it was creeping into Fox News (and eventually we'd have News Max, OAN, etc. that loved to peddle this stuff). Social media platforms that reached hundreds of millions and even billions were dumping this stuff in the lap of your semi-crazy Aunt Edna, who could, with the click of a button, forward it to hundreds of "friends". Magnify that by millions of Aunt Edna's doing the same thing.
Jump ahead a little more and we get a once-in-a-lifetime pandemic that we should have been prepared for - for fuck's sake, the very people who bought hook-line-and-sinker into these theories had been screaming about pandemics and being prepared, and it turns out the preppers couldn't handle staying away from Applebee's or Chili's or Supercuts. It wasn't the idea of the Chinese invading or the government putting them in concentration camps that scared these people, it was the idea they couldn't get a decent appetizer or cheap haircut.
And then the icing on the cake - after we elect a President who was helped by conspiracy theories spread by the largest social media platform, we re-elect him, after he ran on conspiracy theories, including that a known pedophile and child trafficker had files on all the Hollyweird Eleet. The Attorney General of the United States of America tells us publicly that she has the client list on her desk. Our President attends a 9/11 memorial with a fucking 9/11 truther. The largest podcaster with a reach of tens of millions constantly pushes whatever conspiracy theories his guests are pushing. The world's richest man constantly pushes conspiracy theories and the 15th or so largest social media platform that he owns allows that stuff to go unchecked. And then our AG and President say there was no list and the party in power votes to keep the list(s) away from the American public. And our former heroin-addict/bushmeat-eating/brainworm-infected lawyer who runs Health and Human Services and the CDC is telling us we don't need vaccines and that Tylenol causes autism. And we have state legislatures banning condensation trails from aircraft because those contrails are secretly brain control chemicals.
TLRD: 30 years ago, people with minimal critical thinking skills could get by in life just fine, without being bombarded by bullshit conspiracy theories. Now batshit stuff is dropped in their lap every day, and authority figures reinforce it.