One question is, how much immunity is the pandemic itself causing, and will we naturally get to herd immunity, even without a vaccine? We have already had over 200,000 deaths in the US, so that would mean 1-2 million deaths before getting to natural herd immunity. (And again, this is at the minimum 50% resistance for herd immunity). The bottom line is that there is no path to natural herd immunity that is not horrific. There are still some unknowns here, but counting on natural herd immunity does not seem like a viable option, even under wildly optimistic conditions.