As a psychiatrist, I loved the movie. I saw enacted how to change the mind of someone resolute in his decision. Life or death can hang in the balance, as it did in the film and as it does, for example, in mental health care and countless other instances when someone has exited from reason and responsibility.
The reality facing both sides will not change: There are spoilers in the U.S. and Iran who will try to torpedo a deal, no matter the details. Precisely because it is impossible to satisfy ideologues, they only way to defeat them is to have a deal in hand that both sides believe is a win-win outcome.