Unfortunately, wearing a mask in the first days of the pandemic probably would not have made any difference because the virus was already circulating. And, only particular masks like N95 have the potential to decrease transmission but even N95 masks only decrease by 95%, hence the name. N95 masks are not readily available. They are used routinely in various occupations such as painters, in nail salons and beauty parlors. In fact, physicians in New Orleans asked nail salons to donate all of their N95 masks to the hospitals. Supplying these to everyone in a country would not have been feasible or practical. In addition, most people do not know how to use a mask. Think about focus on hand washing. Most people do not wash their hands after using the rest room, before or after eating, and we touch our faces, our bodies, and other people's bodies all the time. How many of us wash our hands after doing all of this? I wish I had an easy answer to this excellent question.