Nice article, I think you’ve gotten a lot right, and i think analyses like this get down to the point where we can have a rational discussion. Here are some counterpoints:
1. Looking at NYC, the fatality rate is roughly 0.5%. This is based on a 20% positive antibody sample, which is getting large enough that the false positives aren’t overwhelming the data any longer.
2. If we take that as a given, then if 100% of the population becomes infected, we will have 1.5 million deaths. If we assume something more like 60%, then just one million people will die. If we lower the mortality rate to 0.3%, then maybe we are more like 750,000. I have a hard time believing it will be much lower, considering that 0.1% of NYC’s population has already died from covid-19
3. Additionally, if we give up on social distancing, then those people will die in a large wave, overwhelming our hospitals.
4. I would love to see a plan that keeps seniors safe and lets everyone else out. So far, that plan is not forthcoming. It’s hard to see how we keep them safe if their family living with them and their caregivers are all infected. So far, we’ve done a piss poor job of keeping them safe in senior living facilities, even with a lockdown.
5. On the comment that the same number of people will die with a flattened curve - that’s only true if hospitals don’t get overwhelmed, which may well still happen. Additionally, it turns out that the herd immunity point, where transmission drops below 1, is actually a function of the base transmission rate. We can actually reach herd immunity at a lower infection percentage if we are socially distanced, and thus avoid some of the deaths.
Ultimately, I think we will find ways to back off the lockdown, but health departments will be on the look-out and will be titrating the degree of lockdown as cases rise and fall. It’s hard to see e.g. restaurants getting back to anything close to full occupancy any time in the next year, and most of them don’t make enough profit per table to operate half-full (or less).
EDIT: additional point to add: yes, it seems that covid deaths will be heavily weighted to seniors. But so is mortality in general. Let’s roughly assume that the mortality rate for covid is 0.08% for 25-35 year olds. Guess what? The average annual mortality for 25-35 year olds is around 0.08%, so it will roughly DOUBLE if covid sweeps through the entire population this year. Covid could easily become the single largest killer of young adults this year.