Maximal extent of COVID-19 in Tennessee
I actually like the backwards method of analysis as well. The numbers I've seen from the CDC (I can't find the exact source, but it's similar to https://www.cdc.gov/coronavirus/2019-ncov/hcp/planning-scenarios.html) on the infection fatality rate of this is it's in the 0.12% overall range, though that varies radically by age.
Let's work backwards from the population of TN. According to the Census, the estimate is 6.83M. The herd immunity number that I've seen often is around 60%. (we can play with these numbers, but it's obvious how you can tweak them.
If you just multiply things out: 6.83e6 * 0.0012 * 0.6 it works out to just over 4900 people dying. We're already at 2864 people having died from this. There's no stopping the virus because it's in every corner of the state. We can potentially slow it a tad, but the end result will be basically the same. Roughly the same number of people will have died.
I get it that this is a spherical cow in space type scenario, but it's to get into the ballpark of what reality is with as few unknowns as possible.
The key is to try to slow the spread to minimize the people getting it all at once. (e.g. there's no concept herd immunity with a massive convention if literally everyone is exposed to it at once since this is a highly contagious thing)
I think my thesis at this point is roughly the same number of people are going to get this when all is said and done. Be careful, but it's not the end of the world at this point. Do what you're told. If you're in a high-risk group, take extra care.