Nakatsuka-san of ZYX is another elderly man who hand makes his cartridges. Recognizing that he won't be able to work forever, he's been training several younger family members. They've been actively involved in making cartridges for a couple of years under Nakatsuka-san's supervision. This legacy is being preserved.
OTOH, consider Herb Papier, who developed and built the TriPlanar (nee, Wheaton) tonearm as a one man craftsman. As Herb neared retirement he searched for someone to assume and protect his legacy. He found a superb candidate in Tri Mai, who has continued to improve an already great tonearm while respecting its legacy.
A legacy can, but need not necessarily, be assured by an in-family succession.
OTOH, consider Herb Papier, who developed and built the TriPlanar (nee, Wheaton) tonearm as a one man craftsman. As Herb neared retirement he searched for someone to assume and protect his legacy. He found a superb candidate in Tri Mai, who has continued to improve an already great tonearm while respecting its legacy.
A legacy can, but need not necessarily, be assured by an in-family succession.