We have a pretty good idea why, but how long will this ratings shift last?
A few of Brian Stelter's points/reasons:
1) Fox focusing on Big Tech's censorship rather than on the terror threat we now face
2) Fox News shows going all in on conspiracies
3) Fox de-emphasizing news programs for opinion shows (that many of their viewers mistake for news)
https://www.cnn.com/2021/01/16/media/fox-news-cnn-tv-ratings/index.html
A few of Brian Stelter's points/reasons:
1) Fox focusing on Big Tech's censorship rather than on the terror threat we now face
2) Fox News shows going all in on conspiracies
3) Fox de-emphasizing news programs for opinion shows (that many of their viewers mistake for news)
https://www.cnn.com/2021/01/16/media/fox-news-cnn-tv-ratings/index.html