If you were a male trader or explorer traveling in tribal areas you would find almost everywhere on the planet that you were offered a bed at night with a woman. If you stayed several nights you would be offered several different women.
How tribal people learned that they needed to diversify their DNA I don't know. But most tribes know that without diverse DNA in the form of children from outsiders, the tribe would not last more than four or five generations. Inbreeding is fatal for small groups of isolated humans and most mammals.
I bring this up because it does not seem to apply to commerce.
Very few businesses survive more than one generation and only a tiny number survive two generations. Many industries do not survive two generations and few industries survive three generations.
There doesn't seem to be a commercial version of marrying outsiders. The necessity for commercial status quo seems to be the dominant force. Businesses and industries resist change. The constant creation of new businesses by new people seems to be the source of commercial vitality.
I merely wanted to point this out because small towns and retail shopping streets in small towns tend to die. New vitality tends to come in new geographic locations.