From my point of view it's the proliferation of sources of (especially monetized) information competing for attention. In the 1970s, major US cities would have

From my point of view it's the proliferation of sources of (especially monetized) information competing for attention. In the 1970s, major US cities would have ~10 radio stations, ~5 TV stations, 2 major newspapers, and no access to online content. It was not uncommon for people to spend an hour of more with their local newspaper each day, and significantly more than that on Sunday. From today's perspective, TV news felt somber. Even frightening cold war developments would be spoken about with the calmest of demeanors. In the 1980s cable brought that to a few dozen channels and it was getting easier to get national newspapers (NYT, USA Today, etc.). The 1990s saw many cable systems with 100+ channels and people started going online in large numbers. Now there are so many options in video (100s of TV channels, YouTube, TikTok, Netflix, Disney+, ...), audio (countless podcasts), and written content (news sites, blogs, social media, ...) that trying to get noticed in order to make money often leads to more extreme content. If people are navigating through hundreds of options per hour, how else can you get a chance to be noticed? Think of things like angry shouting in cable news, click bait, and political "discourse" on Facebook and Twitter. The most successful early examples of this (MTV and pro wrestling in the 80s/90s, shock jocks proliferating in the 80s/90s, Fox News in the late 90s, Twitter and Facebook before 2010, etc.) are old enough that people under 40 years old have always seen some form of it. People under 25 who are most grabbed by it have seen little else. When Twitch streamed Bob Ross for a week in 2015, many young people saw him as a rebel because his demeanor was so foreign to them. People tend to emulate the norms they see, so now you see various levels of it in content that isn't so desperate to get noticed. Mike Judge (a significant part of MTV's success in the 90s) played out where this was heading in his 2006 film Idiocracy. I think it was intended as a cautionary comedy, but it increasingly feels like a prescient horror to me.