Final answer:
Al Capone's health deteriorated due to syphilis during his incarceration, and he suffered from associated mental and physical deterioration, ending his criminal activities.
Step-by-step explanation:
Al Capone, notorious for his bootlegging and criminal operations during the Prohibition era, suffered significantly in health while being incarcerated. Capone was eventually imprisoned for tax evasion and served part of his eleven-year sentence at Alcatraz prison.
During his time behind bars, especially in the later years, Capone's health deteriorated due to syphilis, a disease he had contracted earlier in life. His condition progressed to the point where he suffered from mental and physical ailments, which weakened his influence and curtailed any further criminal activities from within prison.
Unlike the mythical exploits of a gangster who could manipulate the system, Capone's reality in prison was one of diminishing power and failing health. After serving his sentence, he was released due to his poor health but remained a shadow of his former self until he died in 1947.