They are getting rid of him as part of the attempts to deradicalize conservatives. They want to go back to "muh tax cuts, muh patriotism" days. They don't like the anti-corporate, anti-immigration, protectionist, racialist sentiments that mobilized in 2015-16. They've been trying to rock that baby back to sleep for the last seven years.

Ironically, Tucker acts more as a gatekeeper than a gateway, but I think crusty old farts like Murdoch are too out of touch to understand that.