One only has to look at places that didn't lock downs or have mask mandates, etc, yet their numbers also are going down.
Their numbers were much higher in the first place. The numbers are going down partly because many people are wearing masks and locking themselves down. They still have the 10th highest per capita death rate. It would be a lot higher if they had gotten the pandemic in the early months when New York got it. The high numbers of death put the fear of God into many people in North Dakota. They are not all idiots there.
https://www.worldometers.info/coronavirus/country/us/
There is absolutely, positively, no doubt whatever that masks greatly reduce the likelihood of getting the disease. Statements to contrary are ignorant, unscientific, stupid and dangerous. They are no better than saying washing your hands does not reduce the likelihood of getting disease.
Granted, there are many idiots in North and South Dakota. See: