Hi Siavash,
It is true. People learn in different ways. And I myself prefer books.
But to write a book that "works" so people can learn from it requires a huge effort and a lot of knowledge.
Also, it seems that the number of people that are happy with the online videos and classrooms is much bigger than the ones that are not happy.
This creates a big problem to make a book a reality. I myself started one, but I don't have the time (for now), to continue the project.
Too much work. Too little perspective of being compensated by the time spent on it...
I bet there are others like me... :(
In any case, if you have questions, put them here in the forum, and we try to clear the concepts for you.
Cheers!