Today's expert is tomorrow's outcast or loser.

Experts have a vested interest in protecting the prestige of the knowledge they are expert in. If an upstart comes along with information the obsoletes their ideas - just look at what happened to Galileo or any number of other people.

And note, that an expert doesn't even have to be wrong to be wrong. What I mean by this is that an expert in epidemiology may be completely correct from that point of view, but that viewpoint does not include all of the other fields of expertise that might be relevant when making decisions at a national level. Tunnel vision is a crazy thing, and causes normally smart people to do silly things.