on edit: saw your other comment, and you're correct, little over 2 million is the low but totally unrealistic estimate.
From what I'm aware, if hospitals are able to handle the patients, it shouldn't be up to that level.
And the "slow it down" plan is primarily about not overwhelming hospitals.
There are no countries with mass infections where the fatality rate is plausibly below 1%. Of course, when the health system is overwhelmed, the fatality rate can be 4-5%. But let's just look at a 1% fatality rate to start with.
The US population is 327,000,000. Seventy percent of that is 228,900,000. One percent of that 2,289,000; A little more than two million people if we assume 70% infection and an orderly health care system. But that horrible figure isn't plausible.
Because there's more. Claims you can avoid the overwhelming of the health care system are clearly false. Dividing, assuming, unrealistically that the event could be divided evenly through a year, that means that, that many people dying in a year (365) involves 6271 people dying per day and ten times that many people, ~62,000 people, arriving very sick at hospitals, per day throughout the year. And that is far, far more than could be handled by the US health care system.
Moreover, spreading the deaths evenly is inherently unrealistic, the situation of "flattening the curve" (a good thing in itself), can't stop exponential growth as such. If you decrease the doubling time of a exponential curve, you still have a situation where most of the area, most of the deaths in this case, is in the last double. So the even supposedly flattened curve won't let things go smoothly IF we assume "everyone will get this". And that promises not just 2 million but 10 millions (at the 5% death rate). If assume the US current has 10,000 infections, we approximately 12 "doublings" away from 228,900,000 infections (70% of the population). If we slow the progression to year, half the infection will still happen in the last month, with 10% of those "serious", that 763,000 needing attention per day. We're now talking corpses in the streets levels of horror. And we'd have further deaths from this breakdown situation.
And back to the lockdown scenario. My answer is that Lockdowns are absolutely necessary and thankfully it seems likely in most situations they are coming. The figures above should show that alternative is effectively going to be complete breakdown of the health care system and effectively society.
> If you decrease the doubling time of a exponential curve, you still have a situation where most of the area, most of the deaths in this case, is in the last double.
The closer you get to affecting the entire population, the less exponential your curve becomes. Especially if you're assuming that a significant chunk of the population doesn't get infected, you have to have a curve that spends a lot of time slowing down. The max infection rate will be a lot lower than an exponential curve that keeps accelerating until it slams into a brick wall and somehow instantly stops.
South Korea has dealt the infection extraordinarily well and they have a %1 fatality rate. But even halving my figures, you get an insane result, an overwhelmed health system and so-forth.
The closer you get to affecting the entire population, the less exponential your curve becomes.
True but that STILL bunches up the deaths a lot, until are at a significant fraction of the population, the growth will exponential (and another point of realism, it's city by city also but health care is also city-by-city). The parabola shaped curves in the "don't flatten the curve" articles are bullshit (but the "don't flatten the curves" actions still should be done. It's just the idea that these will be enough that is untenable).
Edit: And I know well there are experts putting forward these arguments. As far as I tell, this an expression of sleep walking, cognitive dissonance or similar phenomena where people don't notice that their mental tools lead them to untenable approaches since they have relied on these tools for quite a while.
Edit2: I think the standard approach of health departments is "when you go past containment, you go to mitigation" and that's what they have been taught. The thing here is nations quickly discover that the situation cannot be mitigated and they have to go to containment on a region or nation wide basis - the situation in Italy, what the situation is becoming in Spain, what literally the situation should be throughout the entire world.
With an absolute best case CFR of 0.6%, that's near 2 Million dead. I struggle to think of a larger loss of life on US soil.
Assuming hospitals reach saturation fairly early, yielding a 5% CFR, and we're looking at 16.5 Million dead. That is... a lot. Like we have nothing here to compare that to. To put it into perspective, the US only lost 400 THOUSAND in WWII....
I gotta say this but I don't think we should put forward the position that total lockdown is an irrational position. Total lockdown seems fully rational, not a product of mere panic at all. Total lockdown worked in Wuhan. Absolute and complete isolation inherently results in exponential decline in the fashion that exposure result in exponential growh. It's a drag but it doesn't seem as much of a drag as millions of dead people.
And that is the bizarre thing I'm saying and hearing in the US - "Uh, just let it infect everyone" - "you know that promises to the largest loss of life on US soil ever" - "well, try to slow it down a bit". Jeesh.