Correlation doesn’t equal causation.
I think people do not understand this phrase.
In the case where there is a clear mechanism linking a cause to an effect, then correlation is a direct consequence of causation.
The medical literature contains many studies of mask efficacy, both in lab testing environments and in real world use. Masks work. They are even more effective if everyone is wearing one. And while proper mask use is increasing, new cases are dropping. So the correlation between increased compliance with a procedure that is scientifically established to decrease viral transmission and the steady decline in new cases is very indicative of a causative relationship underlying the correlation.
Anecdotal
You assume people are wearing the proper grade of mask and completely sealing it according to manufacturers instructions. What we see is a bunch of people wearing hand made cotton masks that don’t completely cover the mouth and nose.
I can count on one hand the number of medical grade N95 type masks we see in public. Maybe it’s different where you live.
L