As it turns out, one can cruise for a fairly long time on a strong foundation that was previously created and a dogmatic reputation. For the US, it has both of those working for it. It was well-governed during its rise, thus causing its rise, and also, it was the world's premier power since WWII, allowing it to forge a lasting reputation as the foremost in the world in terms of modern and well-governed nations.
And because of these 2 factors, current governance cannot by judged by absolute current conditions but only by comparison to the past, in the context of world standards and the standards of its rival(s). With lagging infrastructure, decreases in living standards (caused mainly by costs rising much faster than salaries) and increases in crime, drug addiction, slums, poverty, etc..., the US is doing significantly worse than before, which I do attribute to poor management. That becomes even more obvious if you compare it to China, which is outperforming or at least accelerating faster than the US on all the critical fronts for national power (economics, technology, military growth). I can only conclude that the US is sputtering out of power due to its own internal problems and management mistakes but it is still quite fast from the inertia of its previous successes.