Sorry to say it is because he doesn't need to. He knows that the “conservative Christian” will continue to listen to him since he is the loudest “conservative” voice on the radio. This goes back to the idea of the Sunday morning social clubs. The majority of those attending church on Sunday are not well versed in the Scriptures and as such have no foundation for living a Godly life. I would even venture to say that most are thinking that we will get out of the mess we are in as a country by voting the right way...they are still not at the point of turning to God as the one true answer.
You’re right. The socially conservative Christian has no alternative. Certainly not Sean Hannity, best friends with Rudy “The Dress” Giuliani.