There are some areas for which a PhD is a pre-requisite. I currently work at a synchrotron. Accelerator operators, engineers etc. do not all have PhDs, but when you get to the science side I think every single member of the science team has a PhD.

A PhD is the most straightforward path towards involvement in science that needs big, expensive, sophisticated equipment.

The point is to train you to be a scholar, someone who can do original research in the field, as is expected of university professors. To that end, a PhD program includes coursework advanced enough to bring you up to the current state of the research in the subject, and a period of research apprenticeship with your advisor, where you begin to contribute to the field yourself. That's valuable enough to devote four years to if scholar is the job you want. I wouldn't recommend it for any other purpose. Way too much pain.

Lots of people say they got something out of a PhD. Even if they are all biased, doing a PhD is a culturally acceptable way of being unemployed and goofing off.

http://lemire.me/blog/2015/02/25/hopeless-ones/

well i wanted to be a professor so getting a phd seemed like the most direct route.

de Broglie's are rare.