Success without successors is failure. (Hans Finzal, author and speaker)
We probably all know of businesses or charitable ventures that reached great success until the founder/leader died or retired. The successors were never capable of maintaining the growth, and the venture either diminished or shut down. Finzal’s statement provides another gauge of success. You haven’t been successful unless your successor is successful, also.
The student is not above the teacher, but everyone who is fully trained will be like their teacher (Luke 6:40).