“I think the virus loves a closed system of circulating air, whether heated or cooled.”
I see your point, but the virus still has to get into those systems, and unlike Legionnaires Disease (which is a bacteria), this is a virus, and thus cannot reproduce (or replicate) without a host...whereas a bacteria can definitely reproduce without any outside help.
So you’re saying that this virus could not possibly have gotten into the ventilation systems of cruise ships or nursing homes??