Why does biff still blow his chance of getting into college?

Biff blows his chance of getting into college primarily due to his lack of direction and self-awareness. He struggles with the pressure to live up to his father Willy's expectations, which leads him to abandon his dreams and goals. Additionally, his failure to prepare properly for his exams and his disinterest in academics ultimately result in missed opportunities for college admission. This reflects his deeper internal conflict and the impact of his family's dysfunctional dynamics on his decision-making.