Why wouldn't it want this "conformational change" at all temperatures and humidities? Is there something about the change that is only useful in a certain regi

Why wouldn't it want this "conformational change" at all temperatures and humidities? Is there something about the change that is only useful in a certain regime? Human bodies are pretty standardized so its strange to think the outdoor elements might influence how a virus chooses to be inside the body. Or is this some kind of evolutionary meta game where it could blow its load too hard and those genetics fizzle out? edit: Maybe a window must be picked for some reason or another and low humidity low temp is optimal window?