NYC is a drastically different city than even the largest city in Switzerland. NYC has six times higher population density than Zurich. People behave differently, in Switzerland they are far more accepting the social distancing measures than people in the US. You can't compare two cities (or countries) just like that.
And even in the worst affected European countries, the rates of positive antibody tests are less than 20%, which means we have a long way to go to herd immunity.