To be fair, they were simulating an airtight room with zero movement. Even just people walking around would create some airflow -- an HVAC would create both ai

To be fair, they were simulating an airtight room with zero movement. Even just people walking around would create some airflow -- an HVAC would create both airflow and temperature gradient. Blowing the droplets away is effective, but also blowing them in to either each other or a surface is also effective. Evaporation also occurs -- the smallest droplets likely would evaporate long before this model shows them hitting the ground or dissipating. To your final point, I direct you to the hygiene hypothesis -- you definitely want to periodically encounter low levels of non-lethal pathogens. Yeah, people should take reasonable precautions when they are sick, and you should wash your hands whenever they're dirty or before you eat/stick your fingers in your nose (or at least 5x per day just on general principle), but we shouldn't stop having human social contact, and you shouldn't live in a Cleanroom.