What did Shang Yang and other four prime ministers of Daqin do that doomed them to no good end?

The four phases of Qin, represented by Shang Yang, died miserably in the end, because they were too outspoken when they became a powerful country through political reform, which made their reputation in Qin very high, thus threatening the status of the new monarch. Therefore, when the new king succeeds to the throne, they will be killed to establish power.

For example, Shang Yang is a great pioneering work of Qin State, and it is thanks to Shang Yang that Qin State can finally rise again and then recover the land of Hexi and annex the six countries. However, after Qin Xiaogong's death, Qin Huiwen succeeded to the throne because Shang Yang's position in Qin was too high. Qin Huiwen immediately said that Shang Jun rebelled and cracked Shang Yang. Although King Huiwen of Qin said on the surface that Shang Yang's death was forced by the old nobles of Qin State, he was dissatisfied with Shang Yang's political reform, but in fact it was not like this.

If it is really because of Shang Yang's political reform that King Qin Huiwen is dissatisfied with his laws, then King Qin Huiwen will not continue to implement the laws formulated by Shang Yang after his death. Later, Fan Zui died for the same reason. When Qin was the king, Fan helped Qin to formulate the policy of attacking far and near, thus stabilizing the foundation of Qin. And because of Fan Ju's efforts, Qin became the most powerful country among the seven countries, but Fan Ju was finally sentenced to death for his high work.

Later, when Lv Buwei was a businessman, he helped win Man to become the king of Qin, but after Ying Zheng came to power, he also gave Lv Buwei a glass of poisoned wine to commit suicide. Li Si was the maker of the county system that influenced China for thousands of years, but he was finally beheaded after Hu Hai ascended the throne. It can be said that all four of them ended badly.