That being said, how many years have there been a dialogue where films like The Farewell, Us, Knives Out and numerous others were left out of the running because of the cut off? With a 10 picture race guaranteed every year, the theory in favor of the decision would be that with many guaranteed slots, there would be a better chance for unpredictable, dark horse nominees of that sort to make it in.
Article source: https://www.cinemablend.com/news/2548115/will-the-oscars-guaranteed-10-best-picture-field-lead-to-more-unpredictable-choices