We're already a banana republic in all but name.
The USA has an extraordinarily diversified economy and is at the forefront of pioneering the "Information Economy" with companies like Meta, Microsoft, and Apple.
A Banana Republic is a nation that is unstable because it's income largely relies on the exportation of natural resources. This isn't always a bad thing, and I can provide some examples:
1: The income from the exportation of natural resources can be used by the state to "turn around" the nation's economy, such as in the example of Singapore, which was originally a part of Malaysia.
2: A Banana Republic can also be a nation who's economy is centered around agricultural exports. For example, the USA exports ~94.8 BILLION dollars worth of agricultural products per year according to the OEC. That's a lot of money, while agriculture is usually a quite reliable source of income (as the demand for food is generally highly inelastic, while food costs are usually quite low among "western countries"). Sure, Agricultural income is reliant on weather, but for the nations that have Agricultural exports as a major part of their net income, the generally have decent weather (see the USA Midwest, Argentina, Egypt, and Ukraine "pre-war" for more info.)
Run by corporations and a small cadre of "elites".
Well of course, that doesn't make us "3rd world" (3rd world was a term originally used to describe nations that neither aligned with the Soviets or Americans during the cold war, so from now on I'll say underdeveloped).
Profits are privatized while risks/costs are placed on the backs of the public.
Of course profits are privatized, that's how capitalism works. And negative externalities are minimized a good deal by both public opinion decreasing on firms that produce the most negative externalities, which leads to a decrease in units sold and, via proxy a net decrease in profit for said firm, as well as government regulations on firms that produce an excess of negative externalities, such as pollution regulations in the automobile industry. This is not to say that there are no negative externalities placed upon the public, there certainly are, but they are minimized by the government and by the hyper-acceleration of the exchange of information via the internet.
The wealthy enjoy subsidies, protections, and bailouts while everyone else gets austerity.
Yes, this has been the norm since the popularization of the estate system, at least. It is a problem, I'll admit to that, but it is also not one I see being solved anytime soon. Also this is generally not a metric used to measure a nation's development, the most common measures used to quantify a nations development are access to and quality of healthcare, healthcare, macro-economic growth, and sometimes human rights (which is nearly unquantifiable but I don't do these studies).
We can't even provide basic services like health care to all citizens but we can spend endlessly on wars and imperialism.
Perhaps not in the traditional sense of imperialism that involved expansionism (see history of the USA from the Louisiana purchase to the early 20th century when the US had annexed the Philippines very recently and exerted control over the island chain.) Yes the USA has involved itself in imperialistic wars throughout the 00's and early 2010's, but we are seeing a shift away from foreign interventionism, especially with the pull out of Afghanistan (I am purely talking about direct intervention).
As for healthcare, if the government subsidized healthcare it would logically lead to a decrease in innovation in this sector of the economy, as the need to innovate would be lessened. Furthermore, because of this, there would be less decrease in prices of healthcare.
Our government ignores the will of the people to serve oligarchs and the military industrial complex.
Of course they do... this isn't anything new. You are half-restating an earlier point that is a norm across society. The Ottomans had their harem, and the British where heavily influenced by those in rule of the British Raj. Ruling a nation is WAY more complicated than "well, I'm the king, so I have complete control over everyone, and all of my decisions are made without any external influence." This wasn't even true for the Fascist (and I use that term VERY, VERY carefully.) nations prominent in the early-mid 20th century, such as Italy, Spain, Germany, and Hungary.
We have 5% of the world's population but 25% of the planet's prisoners.
Ok THIS is something that I do think you are right about. At the end of the day, what I think may or may not be true, but I do agree with what I believe you are insinuating: that the US had WAY too many people in prison. I'm not exactly sure what we would do to solve this problem, but it may start with a decrease in the profitability of prisons. I also do not think that this is a major indicator of a nations development.
Our police departments are militarized and largely unaccountable.
I'm not sure that this is a quantifiable claim (as many of your previous claims are unquantifiable, but I am quite nitpicky about this and am a hypocrite in this matter. Simultaneously, that doesn't mean that way I say is wrong because of that.), but I do see what you are saying. From what I see, our police department is largely made up of blue-collar working men that recieve little training, but also are usually armed with pistols, tasers, and batons. At the end of the day, I don't think this is a really big problem.
Some nations that are widely accepted as "3rd world" are Yemen, Somalia, and the DRC. These nations don't even come close to the economic, educational, or military metrics as the USA.
I wrote this really quickly I probably screwed up on some stuff so I'll come back tomorrow and edit it.