Final answer:
Congress incentivizes delayed retirement to financially stabilize Social Security, given longer life expectancies and a larger aging population. Increased lifespans and the aging Boomer cohort exacerbate system strains, intensifying sustainability concerns.
Step-by-step explanation:
Congress structured Social Security benefit payments to increase with the age at which a person retires to incentivize workers to delay retirement, which helps to reduce the financial strain on the system. Due to longer life expectancies and a large aging population, there are more retirees and increased spending on benefits. The aging Boomer cohort and the discrepancy between the number of current workers and retirees contribute to concerns about the sustainability of Social Security. Moreover, the Social Security Trust Fund, which holds surplus revenues from payroll taxes, is projected to face challenges as the number of beneficiaries increases, straining the government's ability to fund Social Security and Medicare.