Succession planning for teams (a bit morbid but I am curious).

Cup teams still seem very strongly patriarchal with the big 4 teams being led by very strong but aging leaders. The youngest is Hendrick at 76 and Penske is almost 90. I started thinking of this when looking at the Jesse Love to RCR conversation. It doesn't seem like "retire" is a thing that is in the plans but does anyone know what will happen when these owners are gone? Will their teams carry on with other family members or team members carrying the torch or will the teams be sold. It just seems like the owners are such dominant figures, I can't imagine the teams without them.