On the expert in all fields: actually I just disagree here. I get your point but I think my summary is right. Let's again take the doctor sub-argument. If I decide that because my nephew's college roommate's friend had a doctor who was a bad apple (bad call? Oxy abuser? whatever) that I won't trust doctors anymore then the result will be that I become the medical expert in my life. As I am no longer delegating that competency and expertise to doctors, I have now assumed that role. Then add to that my assuming all the other roles that the top post used as examples and I'm now (in my world) the export (for me) on all those subjects.
I don't know about you, but I have a life and just don't have the time to be an expert on geopolitics, all fields the press is covering, all house repairs, my car, science, my health, and everything else mentioned... (1) For my part? Thank god for qualified experts.
1 - from top post: "Politicians, journalists, contractors, car mechanics, scientists, all experts and all professionals with with trust issues."