Honestly don't follow the news that much, but notice that for all the saber-rattling, China hasn´t actually done anything, in contrast to the US over the last, oh, 200 years.

Honestly, China has had a history of it as well. Though that China technically isn't this china. There were technically at least a China or two between then and now. Maoism was mostly toxic at home. Dengism ramped it up and will eventually export it sooner or later. This China is only just getting to the position where they can start doing it. Which is why they are starting. The main reason that it hasn't escalated into military conflict. Is that most of the people they've been intimidating know that they would lose in that sort of conflict.

I also have a theory that power eventually corrupts society as the powerful enrich themselves to the detriment of their supporting society--the parasite kills the host. It's already happening the United States. I'm honestly wondering how China, with it's centralized authority structure, has managed to not only survive so long, but actually make advancements as a whole.

The same way the US did. If we would be around 250 years post Chinese empire. I would 100% wager you that they will take a very similar path as the us. Because the US did similar to the countries that came before it. And they did similar to the countries that came before them. I'm 100% on the same page with you about power corrupting. That's why it happens and with their centralized system they may not let the information or data out that it is happening. But it is happening.