Secondly, without this historical fact, the root cause of who wins and who loses lies in the hands of the author. Whoever the author tells to win will lose. There is not much factual basis and reason to talk about.
Thirdly, the author's arrangement of plots and characters is based on the needs of the whole book, because his book has two major requirements: first, it should reflect the overall glorious image of Liangshan, a hero group in Shui Bo; Second, he wants to compare the incompetence of the Northern Song Dynasty. Because this book was written at the end of Yuan Dynasty and the beginning of Ming Dynasty, it is popular among the people, so the market for this book is common people. People like and miss the Song Dynasty, but they don't agree with the Mongolian Yuan Dynasty's policy that culture is not important to suppress the Han people, and at the same time they hate the incompetence of the Northern Song Dynasty court. Therefore, the author of this book wants to write the heroes of the Water Margin brilliantly and the Northern Song Dynasty darkly, so as to satisfy the voice of most readers, that is, ordinary people and endow them with this evil spirit.
Finally, highlight Liangshan in Shui Bo and make him invincible. Tian hu, Wang Qing, Liao and Fang La are no match for him. He didn't die on the battlefield behind enemy lines, but was killed by the fatuous court, just like Yue Fei's murder, which coincided with the complex general mentality of the people in the late Yuan and early Ming Dynasties. It's not that we Han people don't have talents, but that the emperor and the court are too fatuous to be ruled by Meng Yuan.
Because of the above reasons, Fang La, as a supporting role, lost to Song Jiang, as the leading role.
I hope my answer can help you answer your question, thank you!