McCain is toast, and he knows it (well, at least his handlers know it). This is his last senatorial term. He will not be returned for another term. He will either retire or lose in the primary. If, for some inexplicable reason he survives the primary and runs as the GOP candidate he will lose then.
McCain attacks conservatives viciously, remember how he savaged Hayworth? He would never attack his friends across the aisle the way he goes after consservatives.
He’ll be back because the people of AZ like their Senators of the cheap labor importing type. They elected Flake knowing he would betray the citizens.