This is also true for me, except that I still put in the hours reading books by authors that I like. So to a large degree what's been lost is the willingness to go ahead and read iffy books.

It makes a large difference, but I think focusing on the presence of "additional distractions" misses something about what's going on.

(I'm not claiming that I spend the freed-up time doing valuable things, or that reading mediocre books wouldn't be valuable - I'm just saying that the fall in reading doesn't apply to the activity itself so much as to the majority of content to which it would apply.)