I think you have misunderstood. PhD has nothing to do with expertness. If you have a PhD, you have completed some kind of research training. That's all there

I think you have misunderstood. PhD has nothing to do with expertness. If you have a PhD, you have completed some kind of research training. That's all there is. Says nothing about knowledge or whether or not you're a genius. You cannot conclude anything else, and nobody claims that you can. If someone has a PhD, they have some training in doing research.