If one would really be interested in these kind of things, I'm pretty sure one would be interested in other great resources, like the one mentioned.
If one would really be interested in classical music or philosophy one would sure not miss the (other) giants in the field instead of concentrating on just one or two.
Interested enough to listen to a lecture for an hour is not the same level of interest as focusing on a book for many hours, basically. The two things aren't comparable in terms of depth, and many people are interested only enough for surface level understanding or intuition?
If one would really be interested in classical music or philosophy one would sure not miss the (other) giants in the field instead of concentrating on just one or two.
There's the mistery.