Is this true? Can it be true? Notice that it says traditional authority figures and not bluntly authority figures. What is a traditional authority figure? I think he means someone you are required to meet face to face regularly, such as a teacher. If so, then I believe this statement is true.
The Web gives you access to other authority figures, some who may be more interesting to you. When I was a student in High School, I was limited to what my teachers would offer me. And frankly, as a general rule, it was poor despite the fact that I went to a private school. Right now, High School students can go much further than what their teacher allow in class. They can discover and meet new people online (through their web sites) who may be more knowledgeable or interesting than their teachers.
I think the same is true of doctors, lawyers, professors, teachers, and so on. They all lost a little to the Web because they now have to compete partially on a worldwide expertise market.