While any debate pertaining to "greatness" holds a certain degree of subjectivity, it has long been a truism that 1939 was Hollywood's best year. Many consider 1939 the apex of the Hollywood studio system. With the Great Depression nearing its conclusion, film budgets began growing larger and audiences flocked to theaters in never-before-seen numbers.
Source:https://www.cbr.com/best-hollywood-films-1939/