[The statement that masks work.] It has already been put to the test. Look at the data from Taiwan and Japan. They have not even started vaccinations in Japan but the numbers are way down, thanks entirely to masks and social distancing.
Why go and look at other countries, especially when the cultures are so different? Look just at the individual states in the US. I don't see much of a difference at all between states with mask mandates and those without. Do you? Data? But speaking of Japan, their cases numbers may be going down (not deaths yet though), but they are also going down in most countries or states now, it appears.
You can also compare cities in the U.S., both now and in 1918. Masks make a huge difference.
Perhaps a couple of months ago I provided a reference that masks were shown to be hardly effective in 1918. But back then masks were often just cotton gauze over the mouth and nose. What makes a 'huge' difference is the type of mask. N95 makes a big difference, surgical masks some, typical cloth masks not so much. This is being generous by assuming one time mask use, something that is hardly adhered to by the great majority of the population.