I actually believe the contrary to be true: if most people were given well-fitting masks that effectively filtered the air, mask adoption wold be much lower. B

I actually believe the contrary to be true: if most people were given well-fitting masks that effectively filtered the air, mask adoption wold be much lower. Because wearing a properly fitted mask that actually filters the air you breath in and out is extremely discomforting after about half an hour. I've used well-fitted 3M 6500 masks a lot for working with nasty glues etc. Those only filter the air you inhale, and have a very broad silicone lip to distribute the sealing pressure. Still it's a lot more uncomfortable than any of the usual Covid face masks I've tried. I believe the two largest benefits of mask wearing as currently implemented is catchment of ballistically travelling saliva from sick individuals, and reduction of hand-face contact in all individuals. And for those two, filtration efficiency is irrelevant.