I think the factor you're missing here is the hospital bed ratio. When folks, even healthy folks, get Covid-19, it can go badly - so all this social distancing is to let it spread really slowly through the populace - maybe so slow we get a vaccine, but probably not... And while it is spreading we'll ideally have enough healthy people to actually care for the sick ones because if you and everyone around you is bed-bound then people can die from pretty trivial complications of the disease including just starving to death.