> Isn't it in the US's interest to some degree to have a stable China rather than desperate and poor?
Yeah, it is. That's what the last 50 years have been. Globalization is a lot of things, good and bad.
We accept university students from around the world and have the top universities (ironic considering our pre-college education). The advantage to us (US) isn't just brain drain, but that those that return are vessels wherein we export our culture too[0] (the reverse happens too btw, but pressure is lower and thus tends to be more selective).
Exporting labor and manufacturing isn't just about making products cheaper. This also helps poorer countries grow and escape poverty (name me a largely prosperous country who is not a significant player in the global market?). Growth (under capitalist theory) happens through the exchange of goods and services, not to be confused with money which is just the proxy for that. China's rapid growth and status today __could not__ have happened without the global market's export of labor and manufacturing to them.
The issue is we all get trapped in our local thinking. We have our own agendas, want to be competitive, and due to this forget how we actually got here and how the underlying mechanisms work. Sure, there was greed and selfish behaviors operating under these systems, but there was also charity and selflessness. You can find whichever one you are looking for, and that part is key.
But now China is rising to be an economic rival of the US, not a economic ally. Were it the latter, I'd wager we'd outwardly be congratulating China on its success (as we had in the years past, and in some sense still do), but behind close doors be competitive. Similar to how the best of friends can also be the fiercest of rivals. Competition is not inherently malicious. But give where we're at, there's two perspectives (realistically more, I'm simplifying) that one can take that are both equally valid and mostly true (they need not contradict). On one hand you can see China as acting as someone who bites the hand that feeds it. China of today would not exist without the west and especially the US. But on the other hand you can see China rising to power despite the US's dominance, that the west was handing over scraps which can be seen as taking advantage of China. Certainly the West in some respect has taken advantage of them, but also China did not need to play in the global market and _could_ have (idk, who does) without the "scraps"/"funding" that the West gave to it.
Of course the US is nervous about a rival, they would be even if friendly. They should be. But if allies I think we would have been better able to focus on our own faults rather than pointing fear (no country is perfect. All have growth. Growth is more difficult when you're at the top. e.g. it is harder to obtain new knowledge through research than reading a book). But that's not the China we see. And maybe that's also the US's fault in some sense. There are many players and it is never one entity performing all actions. Even bad trades have to be accepted unless you can make a good argument that a gun is placed to their head (is a bad trade still "bad" if you'd be worse off without it? Fairness is a very tough subject that's incredibly complex. Way more than we give credit to).
So I'll make a plea. Let's remember that a rising tide rises all ships. That all our countries can prosper through __healthy__ competition. We are able to rise to a post scarce utopian world __if__ and __ONLY IF__ we, the people of our countries, want to make that happen. They have to convince us that we are enemies. But I remind you, the difference between you and me is smaller than between us and our respective leaders. People may be dumb, but a person is smart. People may be mean, but a person and community are kind. Do not miss the trees for the forest, and make sure that you don't escalate any fires. Every decision made in this world starts with something small. Every complex object is built from simple small instructions that simply compound and grow over time and scale. Do not confuse yourself thinking that "I am only one," for you are one and each one is important to this machine built through chaos. Chaos means a small perturbation can have a large change in outcome. Remember that power. You may not be able to control the seas, but you can build a damn and you can build a harbor. Those too have large effects, even if you don't see it. Remember that your ideas are infectious. Like a virus (meme) they capture others. If you like an idea, you have the choice to be a spreader, even a superspreader. The power of social media gives us that capacity, but nature doesn't care which virus wins. People may not be able to choose which virus wins, but you, a person, does. We're only 6 degrees from one another. A pyramid scheme's failure is our advantage. But fear and lies are unbounded in simplicity, while truth is not. This is our disadvantage.
== So that is our choice moving forward, and I want everyone to think about this very carefully: ==
the decisions we are making __now__ will dictate if we go to war and THOUSANDS or even MILLIONS of people die. ON BOTH SIDES. Friends, families, loved ones. Our countrymen as well as just dang old human beings. Each life is precious. It is a negative sum game. Not just for lives, but economics and prosperity. Pillaging may make you stronger, but the world benefits from two healthy competitors more than it benefits from one. You didn't add anything to the world, you only took something away (your rival). We can stop adding fuel to the flames now. We __have__ to stop adding now, because the more we add, the harder it is to remove. It compounds. It already has compounded a lot. But unless we have a time machine, then the best moment to act is now. This is my virus, and I hope it infects.
That is our choice: utopia or (a chance at) "winning"
[0] China has been very successful circumventing this. Deng took great risk when doing this. Not just re-encouraging the creation of an intellectual group, which they had just dismantled only a decade prior during Red August. But there is a reason you'll find Chinese students tend to self-isolate much more than students from other countries, even when those countries have a relatively large local community (e.g. Indians). That insulary nature is encouraged to depress cultural exchange.