An economist could come from the year 2100 with 500TB of economic data and news for the past 100 years, and there's a 0% chance that the public would ever heed their warnings.
It's likely we would get 2 economists from the year 2100 both giving opposite reasons for the next 80 years of events.
As for herd immunity, Google "sweden covid cases" and look at that graph. Then change it to deaths. Sweden is practically done with the epidemic. Cases will never drop to absolute zero due to high testing levels and false positives, but it's now down to tiny levels and deaths have hit zero with no "second wave" in sight. At least based on current data it appears Sweden is over and done with it.
Denmark's got a little over half the population, 1/5 the cases, 1/9 the deaths. Projected GDP is down 5.1% this year, up 4.0% next year, overall down 1.3%.
Norway's got half the population, 1/11 the cases, 1/22 the deaths. Projected GDP is down 4.7% this year, up 3.7% next year, overall down 1.2%.
If you're saying Sweden didn't lock down and achieved comparable economic results to their neighbours, I'd say yes you're right. A little bit worse on GDP, but very comparable. But they also had thousands more deaths, and tens of thousands more cases with uncertain futures, to no economic _benefit_ that I can see.
Sources: - https://www.statista.com/topics/6123/coronavirus-covid-19-in... - https://www.focus-economics.com/regions/nordic-economies
The 20% antibody threshold seems to be fairly common across many countries however, at least outside non-China Asia/Pacific countries that were not badly affected at all. The body learns how to fight viruses and can do so quite quickly.
Some epidemiologist say that we'll live with this virus for 30 years and that pretty much everyone will get it sooner or later. If that is the case some countries have only postponed the inevitable.
Or vaccines or better treatments will soon be available and distributed to a couple of billion people, in that case the harder lockdowns saved some lives or months/years of living.