Great article and ironically short and to the point. For Whom the Bell Tolls is an incredibly dense and complex book, indeed.
The idea that only a few people will make an effort to read complex writing seems a tad elitist to me, but I agree that good is good. Simple is not always best, and our ability to challenge ourselves as writers and readers is so important for our brains, I think, to grow and maintain a high level of critical thinking skills. That is why I try and struggle to read Derrida and others, philosophy, fiction, poetry. The ability to express simple and complex ideas clearly is my ongoing challenge for my own writing.