If Qi Xiuyuan had no choice but to voluntarily abdicate power to Qi Wenchen due to his health issues, that was a special case at most. It was Qi Wenchen's voluntary abdication of the throne to his son that started a tradition in Great Qi.
This was also believed by historians to be the reason why Great Qi had existed for the longest time.
When Qi Wenchen abdicated power to his son in his 28th year of rule, the Emperor Emeritus, Qi Xiuyuan, was still alive. Not only did Qi Xiuyuan get to see the throne passed down to his grandson, but he also saw Great Qi becoming more and more prosperous.
After Qi Wenchen left office, he focused on serving his father. It was not until Qi Xiuyuan passed away that he began to travel around like his Royal Father and Fourth Uncle in their later years and helped his son supervise the provincial governments.