Although people read more today, I think those authors probably have less influence in society overall. Poe is still very popular and Shakespeare will always be held up as the gold standard. But I can see Twain waning a little, Hemingway as well.
On the other end, I see Sartre gaining in importance, Nietzsche too. Not sure why exactly. Although as our society becomes more atheistic, existentialism's popularity has increased. So maybe tastes are just changing. There will always be a place for great book authors. New classics will come along I'm sure.