Zheng Jie had obtained the 3-star title for over 20 years, but he had only worked in the Central Province Academy for five years. Hence, his seniority in the school wasn't high, but it wasn't too low either.
Honestly speaking, if it wasn't for Sun Mo's guidance involving his own benefits, even if one was to beat Zheng Jie to death, he wouldn't jump out to debate Sun Mo.
Once Qin Feng gave up the meteor hammer and switched to practicing with a large halberd, it would be fine if his achievements were passable. But if his strength underwent a huge improvement, where would he put his face?
He would then have to leave the Central Province Academy to find another employment place. Otherwise, if he stayed behind, no one would be willing to take him on as their personal teacher.
If he wanted to obtain the title of a 4-star great teacher, he had to nurture a personal student that could ascend to the Hero Ranking.