We are deeply embarrassed about Sweden.
Supposedly, Singapore and South Korea were proof that this could work anyway, but it seems to have failed in both places - Singapore had to give up and lock down after cases exploded, whilst South Korea also had a whole bunch of spread that completely escaped contact tracing and nowhere near enough testing to pick it back up again, but somehow managed to reverse it through stricter social distancing measures well short of a full lockdown for reasons no-one has explained. I'd be very interested to see what serology studies have to say about South Korea's actual infection rate.
It is hard to imagine SK's infection rate is anything other than very small, given their extremely low death rate (264 for a pop of ~50MM) - to insinuate otherwise is, well, questionable.
Sadly a different dimension has crept into what should be a reasoned public health emergency response. I'm not sure from where, or why, or indeed who - but we should be vigilant, the cost is terrible.
Herd immunity only happens when a critical mass of the population - >70% at a minimum - is given immunity by a vaccine.
This creates a population with a low enough R to guarantee that outbreaks die out, even if some people aren't vaccinated.
Even then it still doesn't guarantee personal immunity, because people in small clusters can still become infected. But instead of a national health emergency which threatens to overwhelm primary care, you get small localised individual/cluster outbreaks which are very much easier to handle.
I think you've got a selection bias there. Those illnesses are household names because they are/were so prevalent. But what of the illnesses that never became prevalent enough to become household names because populations developed immunity fast enough to suppress the spread?
I can't think of any.
TBH, I have yet to hear a decent argument against this, given the following thoughts:
1. Development of a vaccine will take a minimum of 12 months, more like 18.
2. It is not feasible, either for democracy or our economy, to stay locked in/sheltered at home for this long.
3. Thus, the main concern should be to "flatten the curve": keep the infection rate low enough so that, even though people still get infected, hospital systems don't get overwhelmed. I think it's important to note that the only places yet that have had overwhelmed (or close to it) hospital systems had extreme density (Wuhan, NYC), often coupled with lots of mixing of young and old (Northern Italy).
4. A corollary to number 3 is that as long as hospital systems aren't overwhelmed, or close to it, that you shouldn't lock down further. The belief is that the majority of society becoming infected within 12/18 months is inevitable, so extreme lockdowns will do little beyond push deaths out a bit.
5. Do everything you can to protect the highly vulnerable (old, immuno-compromised) as they appear to be at exponential greater risk.
I mean, as the US starts to open up, it is quite clear the virus has not been contained, so for better or for worse the above is the approach we are taking as well.