>A massive economy, industry and war machine are still here
Those things are exactly what destroyed the nation. The military industrial complex and the billionaires who removed the teeth from institutions that used to prevent the accumulation of power (see also: antitrust litigation against Standard Oil). Those entities are now in complete control and democracy is nothing but a sham, a clown show between two faces of the same coin.
The US as a country didn't fail with Trump. It failed when Microsoft got away scot-free. This was the biggest sign that the country was no longer a serious entity, because a serious entity would try to preserve its own power, while the United States of Burgers is something to be sold to the highest bidder.
> Those things are exactly what destroyed the nation
You're confusing the destruction of the dream of a nation with the desrtruction of the nation per se. The Roman Republic's fall was the destructionn of a dream. Those who thought they were witnessing the destruction of a nation, on the other hand, were dead wrong.