That isn't human nature at all, that is a feature of our economy.
The human nature bit is that we are inclined to follow conviction: belief in an idea. And if someone says something with conviction, whether true or not, our first instinct is to believe them, maybe even trust them.
I just wanted to make a distinction between human nature and the benefits of specialization within an economy. You mentioned being an expert in a single domain, which I interpreted as specialized labor, as in an economy
An economy isn't really related to human nature, directly.
