Do Old Companies Tend to Exist in Geographic Clusters?

Recently I've been communicating with a woman from Philadelphia who has an interest in the unique concentration of old companies in the Italian Market area of South Philadelphia.  I have noticed a similar clustering in both Grand Rapids and the Holland/Zeeland area of West Michigan. This observation raises the question of whether it is the community that supports these companies leading to their long lives, or if there is some sort of mutual support system going on among the businesses themselves, or if there is something else leading to these clusters.  My research on 100-year-old companies does indicate that these firms feel a deep connection to their local communities, so perhaps this focus on relationships translates into a support system that keeps the businesses going.

Last week I saw the documentary film "Spinning Plates" which profiled a family restaurant (Brietbach's) in Iowa that was founded in 1861.  It had burned to the ground twice in recent years and both times the community and customers rallied to support the rebuilding.  It seems that many of these old businesses - particularly the generational family businesses - become treasured members of the community that everyone wants to see survive.  I can remember walking with my young children in downtown Holland (Michigan) one weekend when my daughter remarked "we are so lucky to live here."  When asked why she felt that way, she replied "because we have the Peanut Store!"  One of several 'century' businesses located on a three-block long main street, this candy store is one of our community's treasured  businesses, so associated with downtown Holland that if it were ever to close it would feel like losing a dear friend - not just for my family but for many, many others.