Why should there be any need to explain what Ph.D. is to your own Ph.D. students?
May be, they should not be doing Ph.D. in the first place if they don't know what it is that they are doing.
Ph.D. is the new BS and that's that...most of the thesis coming out of schools are worthless (literally).
There is an inflation (big time) in academia. You would know it if you interviewed any Ph.D student on a technical topic.
This is addressed in the second to last diagram, "the world looks different to you now". Once you've specialized so much, you can lose sight of the bigger picture.