> Yeah, no. The dynamics definitely changed, you're not just able to observe more. Think about this from a network-theoretical perspective: how is content- and sentiment-aggregation not only possible, but incentivized through the components which emerged from the economy of attention? How does this affect reflection? Which socio-psychological dynamics were enabled over the course of the last 20 years, and which systemic implications came with these dynamics?
The truth is that a majority of Americans don't pay attention to the news. Yes, there are divergences in the United States on some substantive factors (meaning things that are measured by actual statistical outcomes, and not Gallup Poll opinion surveys), such as life expectancy and general well-being. However:
1.) There is strong evidence that American culture (how people speak, what they wear, &c) is becoming more homogeneous. Look, for instance, at the continued decline in regional dialects, or the on going convergence of American music genres (e.g., the pop-ification of country music or hip-hop)
2.) The divergence in life expectancy and general well-being is largely due to urban <-> rural dynamics, and not regional or Facebook driven tribeification. America is becoming increasingly urbanized, and people in urban environments are more likely to walk more, have access to better food, and better employment opportunities. They are also more likely to come into contact with racial minorities and LGBTQ+ individuals, as well as alternative view points, which is why the American political divide is almost entirely driven by where people live, and why urban countries in otherwise deep-red states almost always vote Democrat
3.) The decline of America has been a constant theme in the American media for at least the last century and a half. It's picked up in the last twenty years, but this is mainly due to the proliferation of media sources combined with the decline of traditional media outlets. Negativity sells. However, this is very much a return to the historical norm and American society will eventually find a way to counter it, just like it did during the age of yellow journalism, or when local newspapers acted as political party outlets. There is also a lot of evidence that "perceived" divergences (the things that you see in Gallup surveys, for instance) are largely media driven. See https://www.moreincommon.com/, for instance