People are reading less and less because we are reading more and more. Let me explain.
We live in a society where we are bombarded by information from all different viewpoints. Often reading more than 10,000 words a day and being exposed to many hundreds of thousands of words. Paying attention to them is a different story, the fact is they are there. The amount contrasted to the average length of a novel (~90,000 words) means we actually read more than the olden-day book-reader.
While I do agree that we should be able to sit down and read something structure, most of us have become adjusted to a life where information comes from everywhere all the time, and that takes away our appreciation for reading.