It wasn't that he was listening to the WHO, it was that he was outright denying the severity and spreading misinformation implying the imminent availability of a vaccine. He's hasn't been a benign pass-through in the development of the situation:
https://www.snopes.com/fact-check/timeline-trump-covid19-res...
Furthermore in what way was the US public health system dismantled? The US was best suited to take on Coronavirus because of its significant number of ICU beds and the number of ventilators compared to the rest of the West. The unfortunate fact is that CDC's tests failed and that left the US flat-footed when it was otherwise better positioned to tackle the crisis than most.