"What about economics or investments?"
Those are exactly the experts who are being most strongly questioned. They are the ones who predicted economic disaster from Brexit and Trump's bizarro-land policies, and yet the wheels have not come off. (Yet.) Therefore, they must not know what they're talking about, right?
> In short, people value expertise in closed systems, but are distrustful of expertise in open systems. A typical example of a closed system would be a car engine or a knee joint.
What about economics or investments? That's a massively open system on which people trust experts all the time. The true deciding factor is whether following (or rejecting) expert advice costs you something. If you have a brain tumor, an incompetent neurosurgeon is going to cost you a lot more than an incompetent president.
In the parlance of Antifragile (which I cannot recommend highly enough for anyone who works with people & systems—so, most of us), the question turns on whether you have 'skin in the game'.