The medical field is pushing their agenda. I don't mean that in a bad way. It's the Hippocratic oath...save all lives. If they save 100% of the population, they've done their job. They're not economists though. What people forget is that it's the job of our governmental leaders to balance on one hand the health and safety of the populace while on the other hand ensuring that there is a country left for them when they are healthy.
But it's a pandemic, not a war. No infrastructure will be lost in the next few months. The economy should be reasonably fine, once we can safely go out again.
The purpose of shutdown is to drive absolute case numbers low enough for a new regime of contact tracing and testing to take over as the primary, far more granular means of fighting its spread.