Why was it unlikely that Wudi would become emperor?

Wudi, originally known as Liu Che, was the son of Emperor Jing of Han, but his ascension to the throne was uncertain due to political rivalries and the influence of powerful court factions. His mother's family, the Wang clan, held significant sway, and there were concerns about his legitimacy and capability as a ruler. Additionally, the presence of other potential heirs posed a challenge to his succession. Ultimately, however, he did become emperor, proving his capability to navigate the political landscape effectively.