Not always. I saw some long article about how outsiders can do better, when you need to be tough. Jews in Europe could lend money, and they would be able to put on their "bankers hat" much easier when they needed to collect debts. There were anecdotes of Chinese-Malays, who would wear Malay clothes when socializing, and traditional Chinese clothes when they were collecting debts; so that their debtors knew not to expect any sympathy.

A well-cultivated network might be valuable, but most people's extended social networks have a lot of deadwood.