I don't really think the longevity of Amis' work is relevant...
Perhaps it is not a fair comparison considering Amis has not had 400+ years by which to be judged. On the other hand, when one artist passes judgment upon another it is not unfair to question why his or her opinion should be given any degree of weight... and what his or her motives (including, but not limited to, jealousy) might be. I assume Amis' quote was selected because it was believed that Amis was an author of some import whose opinions on literature must hold a degree of worth. I countered with the question of just how great a weight we should give to Amis' opinions in contrast to opposing opinions of far greater writers such as Borges, Kafka, Flaubert, and Sterne... to say nothing of Cervantes himself.
nor do i deny that Don Quixote has had great influence on many artists over several centuries.
Of course when offering up personal opinions we can only go our own responses. However there is always the recognition that our personal preferences do not always mirror those of history. The impact of an artist upon his or her predecessors is commonly one of the clearest measures of that artist's merit. The fact that a good number of artists, poets, novelists, playwrights, composers, etc... thought enough of Cervantes book to create a work of art in response to or dialog with it suggest that the work may just have more lasting merit than is suggested.
Even for the contemporary reader who enjoys challenging and difficult works, Don Q might be a bridge too far. Despite its strengths, its static 'narrative', its interminable digressions and its absurd length make it pretty exclusionary IMO.
Similar criticisms may be placed upon many older works of literature. Shakespeare and certainly Chaucer are laden with archaic language. War and Peace, The Brothers Karamazov, Clarissa, The Decline and fall of the Roman Empire, The Divine Comedy, Les Miserables, In Search of Lost Time, etc... are all marked by great length. They all engage in digressions... but these digressions, many would argue, are often among the strengths. Not every masterwork need to follow the compression and the single-minded focus of narrative as put forth by the Pléiade.
While this is not a bad thing in itself, the fact that the book is so rooted to its own time means that many people will not want,or be able, to break through that barrier.
Nearly every work of literature is rooted to its own time to one degree or another. The fully appreciate most poetry one needs to develop an understanding of poetic forms, use of language, metaphor, etc... and these vary greatly from era to era. One does not jump lightly into Dante or Dickinson or T.S. Eliot. They demand... but I would argue they also greatly reward... effort. Even the prose of Dickens or Henry James may be imagined as formidable. Personally, I never found Cervantes to be overly difficult (although this unquestionably is due, in part, to the fact that I am reading him in translation and as such the more archaic aspects of 16th century Spanish have been mitigated). One need know little more than a bit about the romances (Arthurian and those based upon Roland/Orlando and Charlemagne) to have a grasp of the literary context in which the book was written. Beyond that, the themes, to my mind, seem universal enough.
