I rather think if you actually went back and reread that book, you'd discover that it is a pitch perfect example of current culture. No, she wasn't a superb writer, and she was a flawed philosopher, but she was a keen observer of the ills of the modern mind, and for that she deserves credit.
The erosion is "allowed" to happen because the elites have poisoned the university system with their drooling lunacy, political hackery, and endless idiotic critical theories. This means that the academy is pumping out graduates with six figure loans who know nothing real but believe that "toaster oven" is a gender. that "intersectionalism" is an important idea, and that anything traiditonal or Western is evil.
The graduates are thus fundamentally incapable of critical thinking as a group and thus lap up the bottom of the sewer whether it's in the arts, in politics, or in culture. It's not their fault. They were miseducated by monsters who rejected the Western canon and replaced it with hallucinations.
You cannot know what art is good if you haven't studied good art standing on its own merits. You cannot make good art - at least art that is durable - if everything must be first filtered to modern pieties about equality, gender, racism, politics, structuralism, blah, blah, blah. I highly commend Roger Kimball's book "The Rape Of Masters" if you want just a little peek into the complete freight train of stupidity that is the modern university arts program. And it's well out of date now. Things are much worse. The woken-puken are running things ... into the ground.