Studies show it wouldn't work if _everyone_ thought like that at the same time. But studies also show that you need to "pulse" the infection rate among low-risk populations in order to get past this in a controllable fashion by temporarily and partially lifting the restrictions on those people and letting them acquire immunity, while carefully isolating and supporting the high risk populations. The fundamental truth of the situation is: 60-70% will have to go through the wringer before this is over. "When", "which subset", and "how" will determine the fatality rate. One thing is absolutely clear: we _must_ completely isolate (and support) the elderly and those with severe pre-existing conditions. Large numbers of immune people could help with that. Complete shutdown of the economy (if such a thing were even possible) would condemn a lot of the vulnerable people to die, since they still need food and a lot of them also need medical care, which could become unavailable, like in Italy.