The US does indeed have vast resources, but they are spread out amongst various federal and state-wide agencies and entities, along with commercial interests. Our system here is a very fractured, disparate, political system that makes it difficult to coordinate quickly enough to react to something like this.
Frankly, I'm convinced of this: It's too late in the US to be proactive. We're solidly in the reactive phase now. It's no longer about containment. That ship has sailed. Our best hope now is to take whatever steps we can to smooth out the imminent curve of infection spikes, in order to help our system best handle the coming onslaught of patients who will require hospitalization. The Healthcare system will quickly become overwhelmed. We can only now work to minimize that as much as possible. That's our reality that will become apparent very soon. We'll soon have to take draconian measures that until now have seemed unimaginable in the US, if we hope to make a dent in that curve. I'm not confident that we're up to the task.
I hope I'm wrong, but IMHO, I don't think I will be. Maybe I've been spending too much time on /r/coronavirus on Reddit, but this is really going downhill fast.