It's not that easy but its also not impossibly hard. The Audience are drones waiting for their next software update. Megyn Kelly refused to kiss the ring and suddenly she was an evil leftist out to destroy fox news etc.
Hannity has already been reaching out to his audience about the "demise" of Fox and how its turning liberal. The Drones will line up and wait for their next update from their overseers. The Biggest obstacle to a foxnews replacement is the fact the world has changed and advertisers will not just line up
The thing is that we should still cheer this because yes some drones will keep on after their pied pipers but a lot of people probably won't. There's a weird middle ground of people that probably just watch Fox out of habit and it's become a vicious cycle. If that cycle breaks a bit they might not put in the effort to go find where their idiots have gone.
It's kind of like Glenn Beck when he left. Yeah some followed him, but a lot of people didn't. That's good.