Final answer:
Social Security benefits have been a significant factor in reducing poverty rates among the elderly in the United States, providing financial stability after retirement.
Step-by-step explanation:
Among the contributing factors to declining poverty rates among the elderly in the United States, Social Security benefits play a crucial role. The creation of Social Security, alongside pensions and retirement plans, was designed to protect the elderly from falling into poverty after they stopped working. As the average lifespan has increased and many seniors are remaining healthier for longer, they are able to continue working past traditional retirement ages, which also contributes to a steadier income and the opportunity to save more for retirement.