- The physical isolation of the US is one of the reasons it's endured as long as it has, yes. We would be in a lot more trouble if we were physically accessible to enemies, of course. However, not all problems are man-made, climate change is an example of a problem that the US cannot dodge simply because it's geographically isolated. The healthcare crisis, COVID, worsening inequality, etc are all internal problems that the US is unable to address because of its ossified political system. We're not going to be able to ignore those problems forever just because we live on our own continent, we need a functioning government regardless.

Moreover, it is of course trivially true that no two historical circumstances are ever exactly the same. That doesn't mean we discard all historical parallels and lessons from history. That's a very trivial and shortsighted view to the lessons of history.

Obviously the US is not Poland circa 1500. But it demonstrates the problems that can be created from systems with extreme amounts of checks-and-balances. From there we can ask the question "are the US's systems of checks and balances extreme enough that they're causing problems?" and I think the answer is clearly "yes".

- Misinformation has always existed, just like bombs existed before the atom bomb. That doesn't mean the battlefield hasn't significantly changed from 30 years ago. Thanks to the work of Facebook, Google, and others, it is now possible to directly target individuals with the forms of misinformation they are most susceptible to. Just as that has revolutionized advertising, it has revolutionized information warfare, and the regulatory framework has not adapted to deal with that (partially because of liberal absolutism, and partially because of the generally ossified nature of the political system which prevents anything from getting done).

Moreover, back when the government was more functional, misinformation was recognized as a problem and addressed. Truth in broadcasting laws being an example. And as those regulations have been eroded (both legally and structurally with the transition to unregulated forms of broadcast over privately owned carriers) the problems have gotten worse. So yes, it's always been a problem, to the extent that we recognized that and deployed solutions to fix it, and as those solutions have been eroded the problem has come back and gotten worse.

- "Culture" is another trite excuse for systemic problems. It is not the overall cause of the problems. If your system of government and rights framework requires humans to be angels then it is not a good one - this is the same argument as "communism would work if we only found perfect humans". Well, humans aren't perfect, if the US government can't function with imperfect humans then that's a design problem.

But yes, generally the US does have a cultural problem with selfishness and lack of community outlook that doesn't help any of this. People refusing to get the COVID shot while they go around society and (stochastically) kill others and breed new mutations of the virus is just the most recent example, generally you have things like the "temporarily embarrassed millionaire" and the focus on employers being able to use their religion to impinge on their employees' lives that are fairly uniquely american. We would be much better off with some community-oriented ideals to balance out that individualism.

The overall problem is structural, but the cultural problems certainly don't help.