I like reading a lot and think I have learned a lot from it, so I'm biased. But to try to answer your question above:
(1) I can read an awful lot faster than I can absorb spoken or video material, so there's just a volume issue.
(2) Until really quite recently it was difficult to watch TV or movies without disturbing others in situations where you have nothing else to do e.g. sitting on a train, waiting for an appointment at the doctor's/dentist/hairdresser. So it's an additional use of "dead" time.
(3) If you think about a film of a book you've read (I know not all films are based on books, but it's an illustrative point so bear with me), it will leave out an awful lot of the description, nuance, dialogue. Books are a denser form of narrative and information.
I can of course remember things that I've learned from TV and, more so, the radio. But the vast majority of my incidental knowledge has been picked up from books - even really unexpected books (I'm always surprised by the number of things I've learned from Agatha Christie novels).
I think the written word is the most efficient means of delivering information, assuming you are lucky enough to have a brain that absorbs information that way.