Strongest by what metric? If your measure doesn’t take into account political risks, demographic issues, climate change etc, then I question how ‘strong’ we can call it.
I agree there is a large amount of division and political risk in the US.
Edit: but still we are far from the world ending.
More concretely, home buying is a cornerstone of the American economic system, but a combination of income stagnation, student loan debt, and absurd overpricing nationwide has priced out much of the "millennial" demographic. In my local area, shoddy houses are going for $700k, but nobody approaching 30 is buying anything. That sort of thing just isn't sustainable. And this is from the point of view of having a good tech income, which is a bubble.