We’re not protecting only the elderly and the sick … we’re protecting anyone who needs hospital care for other things from overwhelmed hospitals. This thing spreads extremely quickly, and one case diagnosed now likely means 50 diagnosed two weeks later without social distancing measures!
The goal needs to be to prevent uncontrolled spread until we reach herd immunity or a vaccine is found. Of course, this point may come faster or slower in different cities — I suspect that the majority of NYC has already been exposed!