I wonder if national experience rubs off on movies. Many Hollywood movies have historically been optimistic because in general, a the American myth[0] has been pretty much optimistic and triumphalist (until recently, with People's History of the United States maybe the first popular work challenge the myth). Eastern Europe on the other hand has endured centuries of misery. As the war zone between Western Europe and the Ottoman Empire, as the war zone between Protestants and Catholics, as the war zone between the French and the Austrians, as the war zone between the Germans and Austrians, as the War zone between the Russians and Ottomans, as the war zone between the Germans and Russians, as the war zone between the Germans and Soviets, as the war zone between NATO and the Warsaw Pact. This suffering may have caused a certain melancholic outlook on life which is reflected in the movies.
0. The American myth goes that our forefathers came to a wilderness, built the colonies, fought and won against the super power of the age, marched West and conquered the rest of the continent, fought a war to ensure Union and free the slaves, industrialized, saved Europe twice from the Germans, became a super power, saved the world from Communism, landed a man on the moon, and is the shining city on a hill that people all over the world aspire to come to, and other countries envy. Like all myths, there is a lot that is not true, but a lot people in the US embrace this myth.