The "cultural role" is drummed up in order to get people to work on below-subsistence salaries.

It's probably more about ego than money for the high-level people. Since people are cheap (because "passion") they can have large teams under them without their organizations having to pay the typical costs of large teams.

The truth about it, though, is that the culture is too balkanized for any of this stuff to make sense. Very few people go out of their way to read or find the best books; for good or for bad, they've all self-segregated into warring genres and subgenres--and the so-called "literary" crowd who insist their genre is not a genre are often the worst in this regard. The balkanization is probably why no one knows how to market books anymore; people really understand a small slice of the total readership and, in any case, the lines are always changing.