Bill Gates, for example, would make a terrible Supreme Court justice.
It's interesting that you say that, because I had the same queasy reaction to your suggestion about engineers. I'm not one myself, but I envision an engineer as someone who sees problems and wants to design elaborate if clever solutions to them. Good idea when you're building a dam, but not when you're making laws.
An entrepreneur, OTOH, knows the costs of grand government plans built on the "evolving needs of society" and all that nonsense, and views them therefore with the skepticism they deserve.
I grant that Bill Gates, who has long since gone native, would be a poor choice.