I get this question all the time since all I do is train people. And I think there is a lot of great thoughts and conversation here. I could add with a lengthy comment, but it basically boils down to this.

Everyone is at a different space at different times. Some people can grasp tech stuff more easily than others. I know people with Masters that struggle with the basics or even wrapping their brain around what WordPress really is. And depending on the individual I have found I need to explain what WordPress is in a lot of different ways.

And for us, who spend our lives on it, we need to step back and put ourselves in their shoes. Although that may be a challenge, we shouldn't assume everyone can understand a blanket statement of what WordPress is. We all know what assume means :)