As far as I understand, if one is in the same physical distances with the same frequency to others with a mask (a cheap one, not an N95 that is properly put on)

As far as I understand, if one is in the same physical distances with the same frequency to others with a mask (a cheap one, not an N95 that is properly put on), then the mask does not make much difference for the healthy person, but it does for the person expelling viruses. But people are also expelling viruses while you have no symptoms, so lots of people who appear healthy are expelling viruses, and since they appear healthy, they are probably not going to wear masks. For example, if you fly a lot in cramped air cabins, then wearing a cheap mask is not going to do much. What would do something is if every single person wore a mask all the time, since that would capture all the people who appear healthy but are shedding viruses, but that is obviously not realistic. And if you hang out with a toddler that goes to daycare, no amount of masking makes any difference.