> Learning by watching is many orders more popular than learning by doing.

But you hardly learn anything from it. You forget. And you don't know how to apply the bits that stick. You only remember some of the words and concepts. You may repeat them to other people. For 99% (or more) of the viewers, that's enough, because there's never a need to apply probability theory or differential calculus. So it is entertainment. Intellectual, more interesting than most other content, sometimes stimulating, but still entertainment. The 1% that does want to apply that knowledge, really needs to practice, though.