The secret to Fox News ratings success is demographics and niche marketing.
The larger group of reasonable, non-barking mad people spread themselves out over a variety of news sources, even sometimes checking out Fox News to see what they're up to.
But the raving mad lunatics -- and research shows that they REFUSE to listen to or tune into anything BUT Fox News -- ONLY watch the barking mad domestic terrorist training channel. They're locked in, close-minded and drooling with paranoid fear stoked by liars in slick suits, and Barbie dolls with porn star hair and cleavages made with the benefit of modern medical technology.
So in bottom line terms, Fox News gets more numbers, while the greater numbers choose something other than the one network spreading hate of America, paranoid conspiracy theories, racism, and assassination fantasies about offing the president and Democratic politicians.
If there was only one network on the "other side" of Fox News, it would get bigger ratings than Fox. But as there are a variety of other, more honest sources with a greater sense of integrity, the audience is spread out, while the Klan members flock to only one source and one source only.
And also, entertainment always gets better ratings than news.