"The real policy choice is actually whether you lock down indefinitely (with great social and economic damage, and always imperfectly, so that many will die anyway) and wait for a vaccine (that you may never get to), or you attempt to isolate only the most vulnerable and manage the rest of the population to achieve herd immunity naturally.
Complete isolation of the vulnerable (effectively taking them all to medical camps based on government decree) is just not possible in Western societies, and open ended economic closure is just not possible anywhere.
So the only practical policy balance, at least in the West, is a short, temporary shutdown to rapidly buld emergency care capacity, then a reopening and progression to herd immunity, hopefully accelerated by a vaccine and if and when it emerges, making use of the massively expanded care capacity and enforcing selective isolation"
= not a herd immunity strategy, apparently