I believe it has a lot to do with the generations and era we live in.
There was a time where a dinner party consisted of people gathering to have discussion in front of a fireplace after a meal.
Millennials would consider that extremely boring I would imagine.
We live in an era where entertainment has to be quick to the point, action driven, exciting, and contain elements of shock.
Most classic books are (character driven) filled with a host "nuance changes" which slowly reveal an unexpected outcome.
Even older generations are more likely to watch movies, shows, & sports, on cable TV which they're paying (hundreds of dollars) per month. Best selling books today are often written with movie viewers in mind. Hunger Games, Harry Potter, 50 Shades of Grey..
Netflix is also another entertainment vehicle in addition to video games on consoles and smart phones. These are all things one can do with others. Those who have no love life or limited friends do things alone.
Essentially today many people find it difficult to "unplug" nor want to.
Sitting quietly reading a book is almost like taking time to meditate.
In a world that indulges in "social media" and staying connected to others reading a book seems like solitary isolation.
Some folks claim they "never have the time" to read a whole book.