I think it's because Cruz is the real deal. The establishment believes deep down that they can negotiate with Trump, they know they will lose the levers of power with Ted Cruz. And what's the point of having a president they can't control? [sarcasm]
He is not generally liked among establishment Republicans apparently because he doesn't play along with the corruption to get along.
In my opinion, I think the Republican Establishment does like Ted Cruz. Cruz caters to the Conservative agenda, hence, the Republican Establishment likes him.
Because they cannot control him. He actually represents his constituents and doesn't play games.
Kabuki Theater. Ted has been an insider since his college days, he has just been playing his part is all.