Coronavirus affects people of all ages. As it spreads, we are witnessing increasing numbers of cases amongst the young - many of which result in death. If this is about self-sacrifice, it is so across all demographics. The subsequent harm to the working and able population will be more damaging to the economy than maintaining lockdown.
Moreover, '[the right to] life' is an essential part of the US Constitution. Enacting laws that would knowingly, and unnecessarily, put it at risk, are a violation of the principles of state.