Final answer:
The film 'Coming of Age in Aging America' primarily explores the impact of aging on American society, addressing both the societal challenges it poses and the need to change cultural attitudes and perceptions towards the elderly.
Step-by-step explanation:
The main theme of the film Coming of Age in Aging America is the impact of aging on American society. This documentary delves into how an aging population challenges the structures of society, such as the workforce, healthcare system, and the social security net. The film addresses critical issues including the 'graying of the United States', the juxtaposition of an increasing elderly population against societal values that glorify youth, and the global implications of an aging society.