I've been saying basically the same thing. BUT...you can be asymptomatic and spread infection...which leads me to think (and I could be totally wrong) that everyone wearing masks at places with lots of people would be better than none.
that’s why they mandate mask wearing in parts of China, Japan... and why they have the disease well controlled.
The curve has been very flat in Japan. Other than closing mass gatherings, they aren’t really social distancing. Most businesses and restaurants are open.