Well put. Though I believe your argument is a bit of a strawman. As no disease goes "unchecked" in society. We may not have a vaccine (yet), and we may not have as many therapeutics (though many are being used), but we do similarly have testing capabilities and are attempting to regionally erradicate the virus. I think tuberculosis is way worse in that it's been around 150 years and there is no "cure" or decent vaccine. I highly doubt 1.5million people will die of coronavirus this year or next year worldwide. Though it is likely if it went "unchecked" that hypothetical doesn't exist. While we see that coronavirus does have viability in warmer and more humid climates I believe contagion will be somewhat seasonal. In that more sun and humidity will "slow the spread". Sun is good for killing viruses and boosting immunity and viruses suspend longer in dryer air and indoors.
Believe me, I hate strawman arguments and accuse people of it all the time. I'll do my best to correct that impression (or reality) since I thought both your posts on the topic were quite well argued and I don't argue in bad faith on principle. 😀
I think I was a bit imprecise when I said "unchecked" as it isn't a binary. Even some diseases before modern medicine weren't "unchecked".
Let me clarify my point a bit: tuberculosis in its current state is
more harmful than coronavirus is likely to be. I think we agree on that?However, we are comparing tuberculosis with some mitigation against coronavirus with heavy mitigation (as you indicate: coronavirus unchecked is a counterfactual impossibility since we have already started "reacting" to it). But the level of harm we're talking about between these two is merely average deaths and perception of risk. What we also need to talk about is the cost of reacting and the risk over time.
The problem with a negative utilitarian approach of counting up risk quantitatively is that we may mistake a background threat that is harder to avoid (car crash injuries and deaths, cancer costs and death, asthma costs and deaths, maybe even many tuberculosis deaths) with an incomparably immediate threat that can be countered through direct action (perhaps coronavirus, some flu epidemics, the first SARS-COV-1 for sure). Looking at "the numbers" can lead us to mistake "cost" with harder-to-quantify risk over time.
If other countries could do what the United States or Canada did to lessen the threat of tuberculosis, they absolutely should treat that as an emergency until it is achieved. It's hard to say what's needed to be done for coronavirus as it will hit different countries worse (like Italy), and as you suggest we don't know whether it will be less virulent seasonally, or mutate to become more of a risk over time. One possibility that I don't hear people talk about is that something similar to this variety of coronavirus might become part of the human condition like colds, flu, cancers, or tuberculosis. That is a scary thought, but that's not a risk you can shut the economy down over. And I am not a pessimist - we're currently "winning" slowly against HIV/AIDS, some forms of cancer, and a lot of other societal ills.
There have been worse pandemics than tuberculosis. For example: bubonic plague and the Spanish Flu. Spanish Flu was mishandled in its time - if that hit today it would probably look less like tens of millions of people dying in two years and more like what we're seeing with the direct action and passive wariness in response to coronavirus.
Everyone reaches the point where we realize that the individual or collective utilitarian cost is too great to bear compared to the risk, whether that is mitigating coronavirus or any other large social project. Maybe we've already hit that point. Maybe it's a few months away. Maybe we won't even approach it as a society and we will do something approximating "the best that we can" without making undue sacrifices. It's probably too hard to tell right now.
I think you could say I'm an agnostic on the fundamental issue you brought up in your first post. A big skeptical shrug and deferring to the experts, I guess? Death is coming, life is short. 💀🌞