He quite wisely decided that you can either be at the table or be on the menu. If you think he's been hidding under his microphone then you need to get your ears cleaned out because he has done nothing of the sort.
He called Trump everything but a white man for MONTHS, trashed almost everything he said and then SUDDENLY hopped on board once Trump was WH bound. Which is his documented pattern. He beats his chest about 'conservatism' then ALWAYS goes with the nominee, no matter HOW long he spent on his show saying what a bad guy/liberal/idiot/whatever that person was. And like he'd been the biggest fan all along. Because WIN NO MATTER WHAT is what drives him. Not principle.
If you doubt it, you need to look up and learn the history involved.