Big shake-ups are afoot in the media. In recent weeks, digital outlets once valued at billions of dollars have been going belly up, one after another. Buzzfeed announced it would be axing its entire news site, Buzzfeed News, while Vice has entered bankruptcy. Insider, Inc. is letting go of 10 percent of its staff, layoffs are hitting Vox Media and FiveThirtyEight, and the second iteration of Gawker stopped publication earlier this year. It’s the end of an era for massive digital-media companies, including one, Buzzfeed, that once held so much promise, it turned down a $650 million acquisition offer from Disney.

What happened? The answer involves recent shifts in the politics and economics of internet platforms, but also enduring class divides in media consumption.

As many have already pointed out, social-media platforms played a key role in the rise and fall of digital news sites. Where print outlets financed themselves through print and classified ads and subscriptions (with subs increasingly edging out print advertising), digital ads never brought in anywhere near as much revenue as print ads. Instead of advertising or subscriptions, digital media came to rely on traffic and engagement as the primary metrics of success, enabling them to raise millions in venture capital and finance themselves by selling data to third parties.It was the Silicon Valley model grafted onto the news: Reader time spent on the site was your meal ticket, and social media was the primary avenue for racking up page visits for outlets that lacked the name recognition that would send people to their sites every day. Articles that would have languished on little-known web pages went viral when optimized for Google’s search engine or shared on Facebook with headlines crafted to elicit maximum outrage—and maximum engagement.