How is what we are doing anything but approaching herd quasi-immunity slowly [NYC excepted]?
I think the extreme social distancing we are doing is going to result in flare-ups once people do start getting back together. So, yes, eventually it will result in Herd immunity, but only over a period of many months or years (vs. 1-2 months).
However, in the meantime, we will wreck our economy by trying to flatten the curve.
Just my 2 cents.