pre-covid, there were people who would go to school and work when sick. Maybe it will be less acceptable now, especially if there is no loss involved, you can simply WFH.
But “if you are sick, stay home” is not working enough for covid, given high infections before symptoms. But you are right, this should update my forecast. No symptoms is due to novelty of the virus and immune system lag until it starts fighting. After several exposures/infections, the running nose, etc symptoms will occur earlier and then the rules will be to stay home with symptoms and no need for masks after that.