I respectfully disagree. If you measure learning with homework questions from textbooks, then of course textbooks and the modern classroom will seem like the best way to learn. There are many ways to educate. Getting a person intensely interested in a subject is the best way to get them to learn more about it, and Hollywood does intense interest like nobody's business. Someone who associates math with special effects and compelling stories will be more receptive than someone who associates math with boring lectures and homework problems.
Someone who watched a documentary on General Relatively won't be able to perform the necessary calculations to get a rocket to the moon, but that doesn't mean that they didn't learn anything. A higher concept view that makes people say, "Oh, I get why gravity is cool now" could be more useful to most people than homework assignments that don't hold a lot of practical value. Someone is going to be an astrophysicist, needs rigorous practice and skill mastery. Someone who is gong to be a plumber might be better off learning the concepts in an intuitive way that provides an opportunity to learn more.
I think 'knowledge' can be gained from watching these lectures. By knowledge I mean facts. But if you want to learn a skill, you better be slogging on the homework's to gain intuition. I don't think you can learn discrete math by just watching lectures, you'll have to spend countless hours doing problems to learn anything non-trivial.
Someone who watched a documentary on General Relatively won't be able to perform the necessary calculations to get a rocket to the moon, but that doesn't mean that they didn't learn anything. A higher concept view that makes people say, "Oh, I get why gravity is cool now" could be more useful to most people than homework assignments that don't hold a lot of practical value. Someone is going to be an astrophysicist, needs rigorous practice and skill mastery. Someone who is gong to be a plumber might be better off learning the concepts in an intuitive way that provides an opportunity to learn more.