I'm not going to dive into your full post, but suffice to say that you are advocating a policy of capital-c Containment. Your implicit assumption is that we can avoid infection sufficiently long enough such that the future utility of vaccines and as-of-yet-undiscovered treatments outweighs the cost.
My position is that the cost of lockdown massively outweighs the cost of COVID-19 itself, and furthermore I am suspicious of the belief that we can effectively contain it without boarding people in their houses.
> The reason for the lockdown is to maintain healthcare capacity in the face of a virus that is highly contagious.
And yet the lockdown has, overall, scaled _down_ our healthcare capacity amidst the most serious pandemic in a century. Why is that? I can already foresee an argument of "oh well, the lockdown is fine, we just need to pass government regulations that pays hospitals to maintain this extra capacity". And my argument to that is, beyond a general distrust of government incompetence, paying somebody to sit around will not maintain their skills in the same way as paying them to actually perform the preventative care that we hired them for in the first place.
> The OP provides no suggestions on how lockdown might end
But I literally provided a proposal. The proposal is to have at-risk members of population - and yes, we can identify who is at risk really quite easily with the data we now have - quarantine as we've all been doing. Meanwhile, the rest of society is no longer forbidden from transacting and producing value.
Again, if you look at the fatality rate data, you will see that if we can just protect everyone over 60 - and especially everyone over 70 - we will mitigate probably 80% of the deaths. Unfortunately, even _with_ the lockdown, we have utterly failed to do so thus far in many parts of the country.
In particular, I strongly oppose the moral panic around people going to the beach, public parks, etc. Unlike our politicians, I strongly believe that these activities can be done safely and that there is insufficient evidence to show that they were ever a serious transmission vector in the first place.