Same goes for experts. They will be either leaders of industry or PhD's in their field. All related disciplines for a given field will register upon completion of a PhD. Take for instance agriculture. Scientists from various fields from food policy to soil science to agricultural ecology would be put into the pool of candidates available for expert selection.

Many leaders of industry don't have PhD's. What's the process which you want to use to select them?

Why shouldn't a clever politics professor simply hand out 1,000,000 PhD's to people who share similar politics as himself to get people into your expert commision?