Slightly off-topic... but I disagree.
A video, even with multiple angles of each technique, still can't see some of the elements of a technique. In writing, I can describe a weight shift that's not really visible from the camera. I can tell you where you should feel something, or how it should feel to receive a technique. Sure, you can talk about that in video -- but it's just words, and people don't pay attention. If they're bothering to read a book, they're going to read it.
Note that NEITHER books, nor videos, are sufficient for a beginner alone. As an experienced student, I can probably learn some (but not all) techniques from a book or video -- especially if it's carefully put together. But it's still not optimal; there's still no substitute for an experienced instructor guiding you through the learning process.
And I disagree with parts of your post.
I do find a DVD far superior to a book. After all there is a saying,
A picture is worth a 1,000 words. I will add, a DVD is worth a 1,000 pictures.
Better yet, would be a book and a DVD together. For those who would take the time to study both.
I do agree it is better to learn from a real live person teaching the techniques personally. There are limitations to this method of learning, also.
What teacher has the time to devote to one student all his time so that one student learns the techniques perfectly?
What student has the resources to pay the teacher for his devoted time?
At most you get his attention for one hour per day. Maybe three times per week.
Divided by 30 students.
Less days off, holidays, sick time, lazy time.
This isn't a perfect formula, but I'm sure you get the picture.
My books and DVD's, on the other hand are there whenever I need them. 100% of their time, devoted to me.
Now the only question that remains is how much of my time can I or will I devote to them. Since they are available to at all times, I can watch or read at 0200 in the morning, on vacation, while I'm sick in bed, really, any time I choose.
Therefore I don't dismiss them as inferior methods of learning. While I agree, they do have some limitations, they, also, have some advantages.
Yes, I would prefer to learn from a real live person standing in front of me, ideally, I would combine all three for a superior learning experience, combined with a lot of willing training partners and realistic situations.
Until you have to use it in a real situation, you don't know if you have been trained properly or not, regardless of your training method.
Anyway, I have yet to see one of you offer any proof or cite any study indicating learning from a DVD is an inferior method of learning.
All this discussion has turned into, is what an evil, greedy person GM P. must be.