My experience has been different from yours. Everyone I have known well that attained or even sought a PhD has had curiosity, passion, and depth.

However, many of them had narrow curiosity and passion. Engaged within their specialty and their brilliance would shine through, but outside of it they were realtively intelligent but fairly ordinary people.

Of course, there may be a bit of sample bias on my side. The PhD's I got to know tended to be focused on math or a tightly related hard science. They also tended to be the ones that were tolerant of hanging around with someone like me that liked talking about math.