It's an abbreviation of the Latin "philosophiae doctor" == "doctor of philosophy".
Getting one is as much about persistence as intelligence, and makes you very knowledgeable about one narrow area, so what you say makes sense. Academic researchers usually branch out into other fields and subfields as well, but straight out of a PhD, narrow and deep is what you tend to get.
It's an abbreviation of the Latin "philosophiae doctor" == "doctor of philosophy".
Getting one is as much about persistence as intelligence, and makes you very knowledgeable about one narrow area, so what you say makes sense. Academic researchers usually branch out into other fields and subfields as well, but straight out of a PhD, narrow and deep is what you tend to get.