Noah Smith asks a question:

Which of Hayek's ideas are now widely accepted? I can't think of any. https://t.co/byp4vG7QLk — Noah Smith (@Noahpinion) May 9, 2016

I agree with Milton Friedman:

Milton Friedman: “Friedrich von Hayek was a great economist…”

Hayek’s great contribution is this: Competitive markets without externalities populated by well-informed self-regarding rational individuals generate highly productive outcomes because the market has powerful emergent properties that make it an extremely powerful and incentive-compatible societal mechanism for eliciting the revelation, aggregation, and transmission of information about resources, capabilities, needs and desires.

Adam Smith had the part by which societal systems have emergent properties. And Adam Smith believed that the market was a good thing–much better than mercantilism or physiocracy–because it was the “system of natural liberty”.

But in Adam Smith’s thinking, the emergent properties that were good were not those of a competitive market without externalities populated by rational individuals. In Wealth of Nations, the Invisible Hand is one in which the psychological home bias of merchants interacts with an agglomeration externality to produce beneficial results–at least for trading metropoles like Amsterdam and London. In Theory of Moral Sentiments, the Invisible Hand in which individuals’ non self-interested desires to feel marked out above and superior to others induces them to set in motion enterprises that lower their well-being, but raise the comfort and well-being of others. Better for the entrepreneurs that they be philosophers. But better for everybody else that the entrepreneurs are not philosophers, but rather vain seekers of distinction.

Much of what we now see as in Adam Smith–most, in fact, of what Paul Samuelson in his Economics attributed to Adam Smith–is in fact in Hayek.

“…but his contributions were not in the field of monetary theory.”

Agreed. And I would add: not in the fields of political economy or of history and moral philosophy. The Road to Serfdom is a train wreck.