Yes, the randomness between even neighboring countries with similar cultures (say Spain/Portugal) indicates that there's a lot more going on. Good research on the success and failures of Sweden's approach (and therefore indirectly of the general approach of the global consensus) will require much more thorough investigation of the various factors and confounding variables. It's going to be a center of research for years.
I suspect that some things may be ultimately unknowable. But we might also well conclude that some behaviors that a lot of people feel very strongly about don't really seem to have mattered much.
Look how things have changed since even early March. I was at my last in-person tech event at the beginning of March, a few hundred people, and lots of care was being given to not shaking hands and wiping down surfaces but there wasn't so much as a thought of distancing or mask wearing (and who knows how important those things will turn out to be either).
In another comment I mention one piece of research indicating that overall our non-pharmaceutical interventions didn't do much of anything other than small short term effects. There's a fair bit of data showing that while people feel good about masks and social distancing, it doesn't appear to affect the pandemic. However, more focused efforts like protecting nursing homes could've saved half the lives lost in this pandemic (https://www.washingtonpost.com/local/baltimore-nursing-home-...). But it generally takes well trained professionals to do it consistently enough, IMHO.
Portugal and Spain is interesting. Spain response is probably one of the worst in the world, with things getting so bad that the army had to clean out the dead from the living from abandoned nursing homes. I don't think you can compare the two really, since Spain's response seems so chaotic and mismanaged?
I got a feeling that picking the low hanging fruit in time (i.e. concerts, clubs, packed public transport) is enough to not get a big spike at all. Otherwise most European countries should explode since social distancing is no way taken as serious anymore.
> Spain response is probably one of the worst in the world,
I don't think so. This problem is not monolithic. Response is just one factor but not the only, structural factors are other.
An example on structural factors is the population size. Biggest countries will have a higher absolute mortality (more deaths) than smaller ones for example. Just because they had a bigger pool of people vulnerable.
Small ones, on the other hand, could end having a much higher relative mortality.
Is unclear at this point who types of factors have more weight here, but all the hot spots in the first part of the first wave share several common denominators. All except one, and they are structural ones.
Spain and Portugal do not have similar cultures at all. The Portuguese are known for their "brandes costumes", their restrained manners, as much as the Spanish are known for the opposite. That might explain the difference in case numbers.
