Why didn't Zhu Yuanzhang pass the throne to Judy and Zhihu?

Zhu Yuanzhang's original prince was Zhu Biao, and Zhu Biao did have the bearing of being an emperor before he died. After Zhu Biao's death, Zhu Yuanzhang was not old at this time, and Zhu Yunwen, the eldest grandson of the emperor, showed some talents, so Zhu Yuanzhang thought that Zhu Yunwen should be trained as an emperor for the rest of his life, so he didn't choose a prince among his sons. Besides, it was deeply rooted in the hearts of the people in feudal times.