To comprehend Solzhenitsyn's insight one need do no more than compare one of Dostoevsky's novels to one written by his contemporary George Eliot. Russian literature tends to focus on grand religious, moral, and existential themes, while much of Western literature is more tempered and preoccupied with the secular themes like social status and the pursuit of wealth and happiness.
I am not sure if this contrast between Russian and Western literature still holds true today. I have not read enough contemporary Russian fiction to discern if the generation of writers born after Solzhenitsyn are still inspired by great spiritual, religious, and moral themes of the same caliber that possessed writers like Dostoevsky and Tolstoy. I do not know but I am curious to learn if the younger generation of Russian writers - those for whom communism is just a quaint, fuzzy, early-childhood memory - still focus on the "dividing line" that "cuts through the heart of every human being." I am hope they do, but somehow I doubt it.
There is one thing of which I am sure, though, and that is the path literature in the West has taken in the past twenty or thirty years. The essence of Solzhenitsyn's view about Western literature still holds true for some works written in North America and Europe, yet the secular focus of social climbing and self-realization are yielding to much simpler literary themes, namely vulgar pleasure and mindless distraction. To be sure, this kind of slop has existed in some form or other in the past, be it in the form of a Victorian-era penny-dreadful or the writings of the Marquis de Sade, but I would wager society has never been as flooded with as much literature of pleasure and distraction as it is now. The advent of accessible self-publishing and e-publishing has only exacerbated the trend to aim low and use the written word to transmit nothing higher than cheap thrills and semantic sexual stimulation.
Many could argue that this is all fine and well and not worth worrying about. My response to such flippancy is this: it could be all fine and well and not worth worrying about if it were not for two troublesome points:
First, the slop has taken over the mainstream. The success of slop creates the "need" to publish more slop. Publishers are swerving away from traditional literary fiction and are actively on the prowl to discover the next 50 Shades of Grey or any some other tripe that will pad their sagging bottom lines. Even more disturbing is the recent trend to include this slop in pedantically idiotic university literature classes.
Second, and more disturbing to me, is the notion that a society's literature, regardless of its purpose and underlying financial motivations,serves as a direct reflection of society itself. Like the old adage you are what you eat, I believe a society is what it reads.
Though Solzhenitsyn foresaw the decline well in advance, I imagine he would have been utterly unsettled by the precipitous decline of literature in the West. Perhaps he would have even gone as far as to claim that the war between good and evil in the West had come to an end or, at the very least, that it appeared to have tipped in the favor of the forces he scorned.