Interesting, to be honest I was expecting the thesis to be along the lines of "people cannot write because they cannot think clearly". It seems to be that with so many distractions and information overload, the science and art of thinking and articulating ideas clearly are considered as less important.

Edit: I also feel (highlighting "feel", since I don't have data to back this statement) that people tend to read less structured and long content than before (as opposed to tweet-like content and short click-bait articles). Not sure how this influences how society thinks and writes.