Yes, several. They all seem plausible as well, which doesn't tell me anything about any of them being true or not.

1. The US mass media's race to the bottom as previous/traditional revenue models and funding mechanisms fall away

2. Rising economic hardship and income inequality causing greater widespread dissatisfaction with the status quo

3. App-based "free" social media in general where engagement time is prioritized above all else (Facebook didn't invent this)

4. The growing influence of big tech and financialization (SV and Wall Street) and the waning influence of the american worker

5. Demagogues

6. The death throes of the US political parties as they thrash about in a desperate push to try to stay relevant, resorting to simple and effective scapegoating and tribalism

I'm sure you can probably toss out a few more plausible ones, too.