You're so right about how authors used to write largely for white men, especially those educated at elite Eastern schools.

In talking about a "dumbed down" culture, I was referring mainly to what's been happing in recent decades. As I mentioned in another comment, I've heard lots of college profs who've been teaching for decades say that their students' writing and reading abilities really are getting worse. I wish it weren't so but am pessimistic about whether the downslide can be arrested.