Populism has always been about mass distrust of the political establishment. What is emerging in America today is a lack of confidence in anyone, regardless of his profession, who looks like a member of the elite. Hence, the widespread preference for medicine for livestock over the vaccine in Trump states; even the family doctor is no longer above suspicion.
Why is this happening? Because the GOP has been putting out the anti-establishment message (even, absurdly, in states it controls) for years, and because it provides great economic opportunities for right-wing grifters. As Paul Krugman often notes, it is no coincidence that so many intellectual leaders of the GOP sell snake oil on the side.