Scientology is considered a fringe belief group by many and managed to get hundreds of thousands of adherents long before social media. Just as an example that everyone always brings up, advertisers didn't stop the New York Times and many other allegedly credible sources from falsely claiming Iraq had WMDs, the result of which has killed approximately infinity times the number of people that QAnon has. Just like social media users, legacy media outlets distort the truth and stir up rancor in the populace ("hands up, don't shoot", president is a secret Russian agent, Obamacare is a government death panel, climate change isn't real: pick your poison).