Unfortunately, Trump won't be able to accomplish anything as President if Democrats and establishment Republicans (about 80-90% of the GOP) in Congress form a united front against him, as they would do if all of his cabinet selections were along the lines of General Flynn or Steve Bannon. He needs to get at least a majority of the Paul Ryan/Mitch McConnell wing of the party on his side, which is why his cabinet picks alternate between the sort of people we would like to see and the sort of people that Paul Ryan likes to see.
Not an ideal situation, but it's realpolitik - making the best of a usually bad situation.