First, it's not everything. You must learn martial arts from other schools to do the same thing to others. To put it bluntly, it is to learn each other's martial arts, know each other's weaknesses in martial arts, and then practice each other's martial arts very well, in order to do this.
Second, stones from other mountains can attack jade. While learning other people's martial arts, Mu Rongfu's own martial arts accomplishment is also improving. The most classic example here is that in the process of fighting Duan Yu, Duan Yu's six-pulse Excalibur is powerful, but it can't completely restrain Mu Rongfu. Mu Rongfu used many weapons in a row. Although the weapon was finally broken, it could be used as a dart with a brainwave. If Duan Yu is not smart enough, he will probably be killed. The biggest gap between Mu Rongfu and Qiao Feng is actual combat experience. Qiao Feng has passed the test of life and death, but Mu Rongfu is rarely in danger.
Third, it is difficult to move the bucket star to the highest level. The Murong family produced a world-beater Murong Longcheng. However, because Song Taizu rules this country, there is nothing in this life. In Jin Yong's novels, the older the martial arts, the higher the realm of sweeping monk's martial arts. Everyone has a class, so Murong Longcheng, who is older than sweeping monk, is at least the same level as sweeping monk. He is a rare martial arts wizard in a hundred years. Although he left the martial arts in his family, it is difficult for future generations to practice it. Mu Rongfu and even Murong Bo can't compare with Murong Longcheng, so they have to find another way.
Fourth, the origin of family studies. Murong Bo learned martial arts from all walks of life, and Mu Rongfu inherited his legacy and made great efforts in this respect. In addition, Wang Yuyan's family background can provide him with many secrets of martial arts, so it's not stealing, but learning from other countries at most.