What makes you think it started as a publicity stunt?
I actually listened to what Trump said in the Arizona speech. He called out Hillary, Yeb, and Obamba and explained what he would do if elected President. Why doesn’t anyone want to listen?
But regardless if it was all a PR stunt or not, he's winning and he's not going to walk away from an opportunity like that as long as he is. That's my point. If anyone thinks "oh he just wanted publicity", I don't think it's true now even if (IF!) it ever was.