Earlier quoted context omitted.
Because most of the great intellectual works exist in these "legacy form factors."
Of the past yes, but what about the present and future?
The modern stuff feels like total fluff compared to a book, which in turn feel like total fluff compared to the academic papers it is based on. These days I would rather spend 2 hours reading a good book or paper than 10 minutes watching an engagement-optimized edutainment video.
And for the really good stuff you have to go even more legacy – conversation with an expert. A medium older even than books. That’s where you get the stuff that hasn’t made it into papers yet, let alone the downstream half-digested edutainment stuff.