Things are actually looking quite good in that respect. At the six month mark, B- and T-cells which represent the immune system's memory are very robust.

That said, let me add a little more cold water to your refreshing splash - humans have never yet acquired herd immunity to any virus without a vaccine. Not the common cold, not the flu, not HIV, not polio, not herpes.

The most likely result of an attempt at herd immunity for COVID-19 without a vaccine would be very roughly million deaths in the first year, and then a "COVID/flu" season each year for the rest of time which would kill five times as many as the regular flu season did.

Oh, people would get used to it really fast - because people are suckers. But it would be a disaster of immense proportions.

(Me? I have barely left the house since March. I see one friend, always outside, on bikes. I believe in the germ theory of disease and I love life.)