Thomas Kuhn influenced Rothbard by demolishing the notion that the history of science is one of continual progress. The truth is that once a paradigm becomes established, its basic tenets are not questioned at all until major problems crop up.
The effects of COVID-19 are not evenly distributed in the United States. Only certain regions are facing sizable strains on their resources. A nationwide lockdown would create huge economic costs for regions where the the costs of disease have been relatively low.