There are enough factors at play that one can pretty much produce any conclusion one finds pleasing, by a suitable selection of observations and speculations. Here are a few more puzzle pieces for people to arrange into whatever theory they want.
Many textbooks start as lecture notes, and for many others, their pre-publication drafts are used as the basis of lecture courses. Read their prefaces to find examples.
A course of lectures is addressed to a narrow audience: one roomful of people studying that course, who are known to have the prerequisites for where the course starts. A book is addressed to a wide audience: anyone interested.
You can have a conversation with a lecturer more easily than with a book.
There are good and bad lectures, good and bad books, and good and bad web pages.
In the civilised world, status is generally obtained by doing things that people value.
ETA:
6. Speech passes; text remains to be studied for as long as it takes.
7. Some people can explain things more easily in speech than in writing; for others it is the opposite.
There are enough factors at play that one can pretty much produce any conclusion one finds pleasing, by a suitable selection of observations and speculations. Here are a few more puzzle pieces for people to arrange into whatever theory they want.
Many textbooks start as lecture notes, and for many others, their pre-publication drafts are used as the basis of lecture courses. Read their prefaces to find examples.
A course of lectures is addressed to a narrow audience: one roomful of people studying that course, who are known to have the prerequisites for where the course starts. A book is addressed to a wide audience: anyone interested.
You can have a conversation with a lecturer more easily than with a book.
There are good and bad lectures, good and bad books, and good and bad web pages.
In the civilised world, status is generally obtained by doing things that people value.
ETA:
6. Speech passes; text remains to be studied for as long as it takes.
7. Some people can explain things more easily in speech than in writing; for others it is the opposite.