I can doubt some of the more specific claims, but it would be a fairly remarkable result, unlike almost any other area of human activity, if there weren't some sort of person-to-person variation in the [(amount person X gets out of a textbook) - (amount person X gets out of a video on the same subject)] function. The alternative would be the hypothesis that learning ability varies in a 100% correlated manner (people who are more skilled at picking up physics from physics textbooks are exactly as more-skilled at picking up physics from physics videos, and vice versa).

Even if you ignore the visual/textual/etc. distinctions, they have other properties as media; for example, textbooks are easier to use in a random-access/skimming manner than videos, and can be more easily taken outside or marked up. It could just be my concentration, but I also can't get through watching a YouTube video, while somehow I have no trouble reading through a book.

I don't know about theories, but I don't learn as well from video as I do from text. And that's beside the point. The information isn't as accessible as Astrohacker claimed.

Even if you do learn reasonably well from video, you:

* Need to know what to look for

* Need to somehow know which videos are made by people who know what they're talking about

The same applies to text.