gmwilliams...that is a very interesting question...I come from a large family, that years ago was clannish and then after the " matriarch " passed, it totally fell apart. She was the nucleus, that kept it together , thus I feel in every clannish group there has to be a leader. Respect is prevalent , When there are many children, there is a connection between them, someone to spend time with, share thoughts etc, they tend to rely on each other more. Whereas when there are 1-2 children they require more parental attention, thus perhaps jealousy is a factor between the siblings.
To be honest my feelings are when the parents and grandparents have a healthy relationship families will not stray and fall by the wayside , regardless whether there are 1-2 or more children.
Many of the problems in society today are " DYSFUNCTIONALITY " and not accepting responsibility for anything they do in any way shape or form.
Look forward to others thoughts.