I agree to a large extent. Yet, what we see going on in US political leadership truly is beyond my belief of what reasonable adults should do and act like, even as an (precocious, sharp) ex-child.
It doesn’t mean this is the end of the USA. All civilizations go through ups and downs. This is, at least culturally and politically, a down.
I also think it’s global though. The US is manifesting it clearly and starkly, but that’s kind of US style. Authoritarianism backed by populist grievance politics and venal corruption are on the rise around the world.