Before covid, few did except for surgeons during procedures or dentists during procedures. Docs making rounds hardly ever wore masks in the before times.
Even back then there was no evidence masks help prevent the spread of flu or other respiratory diseases.
On one hand, I can see how it is easy to believe masks work -- it is very intuitive. But the history of medicine is littered with intuitive interventions that were later proven to be at best useless or at worst harmful.
Hospital personnel wore them when tending to patients with communicable diseases and those with compromised immune systems before Covid. During severe ‘flu outbreaks, even personnel in doctors’ offices wore them and encouraged patients to wear them, too, especially elderly patients.
Asians wore them routinely out in public during flu outbreaks years before Covid. How well they work is still being studied.
All I know, is, if I’m caring for a cancer patient and his doctor tells me to wear one, I do. If I went against doctor’s advice and gave that patient a disease his compromised immune system couldn’t handle, I’d die of guilt. If I wear the mask, wash my hands all the time, etc., at least I know I’m doing all I can. He might still catch something despite my best efforts, but at least I made my best effort. It’s just how I am. You might be different.