I agree. Reading and writing is significantly harder nowadays because there is no established corpus, hence a lot of literature falls back again to work upon archetypal themes.

But to add to your comment, writing is always based on former writings, and one of the great achievement of modernism is a more conscious awareness of the sources at work in the creative process, seeing the potential this had to exploit it for intertextual purposes.

Elliot greatest achievement is, to put it in your words, creating a conversation, a dialogue, between vastly different sources, to make something wholly new emerge - this is more clear in his latter work, like Four Quartets.