There is as much difference between the stage and the film as between a piano and a violin. Normally you can't become a virtuoso in both.
Source: The New York Post/ 6/7/1956
-- Ethel Barrymore, (Aug 15 1879-1959), US actress; The First Lady of the American Theatre starred in Corn Is Green, 1942; won Oscar for None but the Lonely Heart, 1944.