First, because many — likely most — people simply won’t observe a lockdown at this point. Indeed, many people are no longer willing to abide by even more modest restrictions like masking. If your policy is to do something that won’t be done, you don’t really have a policy. Moreover, the unvaccinated-by-choice are in many cases less likely to limit their behaviors in other ways. The COVID-conscious, in other words, are mostly protecting people who don’t really need it, because they can do little to protect those who do.

Second, even if there were a high rate of compliance, Delta and Omicron are so contagious there is no plausible non-pharmaceutical intervention that could contain them. The measures we used earlier in the pandemic were only partially effective then. They would be completely overwhelmed now. At best, we might modestly slow the spread while it continues to scythe its way through the population.

And third, we no longer need to flatten the curve. Early in the pandemic, we needed to buy time to understand the virus better, to develop treatments, and to stand up a full-fledged testing-and-tracing infrastructure to facilitate containment, which we never did. Since containment has comprehensively failed, most everyone on earth will either be vaccinated or infected eventually. We now have enough vaccines domestically to cover everyone multiple times over. So what exactly are we buying time for?