I think humans have trouble caring beyond their immediate tribe. And a million years of evolution shaped a mind that can't pivot in 150 yrs to a broader sense of community. Look at the countries with high scores for unity, health, well-being, etc. They are all small countries with one language, one skin color, one history, a gene pool that damn near makes them cousins. It is easier for those 5 or 6 million to care for their whole nation because it looks/feels like an immediate tribe. That in you helping someone else you can rely on them following shared rules and you can expect reciprocity.
But when you have 350 million speaking a hundred languages, exhibiting 1024 bit color palette, countless religions, and countless very different life experiences, it is hard to get the individual to pitch in as there is no sense of helping yourself, your immediate family/neighbor, and little by way of common rules/expectations. So, many many Americans just hunker down, clutch their pursestrings, and chalk the whole thing up to unavoidable evil shoved upon them by scapegoat X.
I am not optimistic that the human mind can evolve fast enough to change our direction. A common existential threat is really the only proven tool, but we lost that when the Berlin wall came down. So in a vacuum we turned against one another. Will China emerge as a "unifier" or have we already disintegrated too far to rally? Time will tell - but that type of unity doesn't really create broader solutions, just glosses over them.