Answer
James Dunn's popularity waned in the late 1930s due to the decline of musicals. Dunn was known for his roles in musicals, such as "Gold Diggers of 1933" and "42nd Street", but as musicals fell out of favor, so did Dunn's career. He continued to work, but his roles became smaller and less prominent. By the early 1940s, Dunn was largely forgotten by the public.