The way art and natural history programs have evolved - from "Civilisation" to "Civilisations", from "Life on Earth" to "Planet Earth" - as cameras have improved, the focus has become more and more on these incredible images they can now capture and create, and the proportion of commentary and explication has steadily dwindled. If you watch Civilisation or Life on Earth there are some amazing images but there's also SO much narration, it's like you're in a university lecture, almost.
One view would be that dwindling attention spans have forced the creators hands. Another view - that the creators hands (liberated by technology) have eroded the attention spans. It's probably a bit of both.
And must point out that I think "Planet Earth", at least, is a masterpiece of filmmaking.
Perhaps this has nothing to do with your thread, Version, which is more about the economic imperative to churn out more content/junk. And also, the intellectual decline of mainstream culture. Is there a popular philosopher in our culture? A popular thinker? Most people's idea of a public intellectual now would be Stephen Fry!