I'm not disagreeing with you. Having them and enjoying them is the up-side. The obligation to make sure they stay in the family sounds like it might be difficult, but if people in the family actually WANT the cars then I think what you are talking about is really special.

FWIW, I have no children or nieces/nephews or siblings that would want cars ever. So I can't keep them in the family, although I would like to have been able to if that were a possibility.