Most books - even popular ones - quickly fall into obscurity and out of print. Here is fascinating insight into the phenomena.
The literature taught in schools is that which has survived: a collection of gross statistical anomalies. This is misleading. Falling out of print is a book's natural fate. We can belatedly train ourselves to believe that this will happen to other people's books. What's hard is for writers to believe it will happen to their own.
It'll happen just the same. It happens faster in mainstream fiction than it does in Our Beloved Genre, more slowly for nonfiction history books, very fast indeed for computer manuals; but in the end, all but a very few titles will be forgotten. Just look at the authors in that collection of bestseller lists. You're a literate bunch, but have you ever heard of Harold Bell Wright? How about Mazo de la Roche? Mary Roberts Rinehart, Lloyd Douglas, Irving Bacheller, Frank Yerby, Coningsby Dawson, Warwick Deeping? These were all notable authors in their day. Some of their books were no better than they should be, while others were genuinely praiseworthy; but all of them spent some time perched on top of the commercial heap.
All gone, now. We shall none of us escape obscurity.