Technology is partly responsible for the death of the newspaper, to be sure. In these days who wants to be handed a hunk of old wood printed with yesterday's stories when one can devour raw breaking news Tweets before the mainstream journalists even see the info?
Ideological faux-polarization is, I would argue, another explanation for the decline of print (and mainstream broadcast) media. I say "faux" because today's journalism gives the impression of being deeply and sharply divided on political and ideological lines, while in fact both ends of this "great divide" share much more in common than they would like to admit.
Case-in-point is last weekend's blockbuster piece by Pulitzer Prize winning investigative journalist Seymour Hersh on how Trump Administration claims of an April Syrian government chemical attack on civilians was bogus and the president knew it but fired off $60 million in missiles as a show of force anyway. This is a legendary investigative reporter whose work spans six decades, but he could not find a publisher in the US media. Not even the "Trump-hating" media! He had a publisher in the London Review of Books, which paid for the piece but got cold feet because, as Hersh said, it did not want to be “vulnerable to criticism for seeming to take the view of the Syrian and Russia governments when it came to the April 4 bombing in Khan Sheikhoun.” Even if he was right, they didn't dare report that the US government was wrong! So much for the press as society's watchdog on the powerful.
The US mainstream media has become nothing but a mouthpiece for the state -- or the deep state. Hersh made his name exposing the horrific My Lai Massacre in November 1968. His dispatch was picked up by more than 30 newspapers and made his reputation. Today he has to go to the German press to get a piece of similar importance even published. Shameful.