We went from specious claims and conspiracy theories being the subject matter of newsletters to their public broadcast to millions via talk radio ~and Fox News~, thus allowing people to descend into their own bubbles without ever having their views challenged. Now people seem to rely on social media to give them the same experience. When challenged too much people just pull up stakes to insulate themselves: voat, parler, and private facebook groups are only three recent examples.
It'll be interesting to see if whoever replaces Ajit Pai holds a different view on public intercourse over the airwaves.
Edit: Well as some people have pointed out, Fox News would have been exempt from the Fairness Doctrine as a cable network, i.e. it doesn't use the public spectrum.
As Wikipedia says "The channel was created by Australian-American media mogul Rupert Murdoch to appeal to a conservative audience, hiring former Republican media consultant and CNBC executive Roger Ailes as its founding CEO." So my personal view that Fox (among others) is responsible for a) exposing millions to fact-free content without opposing views and b) people got used to that and don't like it when it's challenged created the bubble we have today. I'm wrong that the Fairness Doctrine would have prevented Fox, although it might have prevented talk radio.