When will digital assistants like Siri or Alexa become human-like? When will we interact with them like people? Will they become friends, or more-than-friends? What if they could replace the dead? Those are some of the questions raised in the new movie “Marjorie Prime.” Based on the play of the same name, the film takes place several decades from now. In the opening scene, an elderly woman is sitting in her living room talking with a young man. He’s her dead husband brought back to life as a hologram when he was young and handsome.