In any year, the overwhelming majority of directors and actors are not nominated. The case that overwhelming sexism is responsible for them not getting nominated when somebody was not-sexist enough to bet a truckload of money on Gerwig and the public was not-sexist enough to make it a fabulous hit. Citizen Kane, 2001 a Space Odyssey, Pulp Fiction, Brokeback Mountain were all a bust at the Oscars despite being far more memorable than the winners. It isn't automatically sexism when a movie made by a woman doesn't get nominated. A more likely explanation is that the movie was so universally lauded that most voters probably assumed it was a shoo-in and spent their votes on movies that seem in danger of being overlooked.