Unlike in movies, most smart people aren't good in chess.
Sure, playing chess needs intelligence, dedication, and good chess players are smarter than an average person. But it's waaaay exaggerated in movies. I'm a math researcher, and in any movie, my department will be full of chess geniuses. But in reality, only about 10% of them even play chess.
Looking back at those games I could recognize ways in which I was beaten by two moves in hindsight. But I had no idea about macro such as controlling the center or moving out the knights early were generally advantageous moves.