Spain and Italy are also somewhat lower than Germany, Austria, etc., which would fit the theory of just having more cases early, but Belgium and the Netherlands (also early high rates) are much higher. Also, per capita mortality in Sweden and France is quite similar the entire pandemic, but France seems to be seeing more of an uptick.
But, again, it will be an anomaly more in need of an explanation if it actually persists for more than a week or two, and there is still at this point the possibility that it is simply a delay in spiking upwards compared to the rest of Europe rather than not doing it at all.
The countries that had strong outbreaks like Spain and Sweden have quite good numbers. Sure, testing ratios make it difficult to compare, but I do believe that many people probably caught it and those that survived are probably less likely to spread it further.
Still, by absolute numbers of dead Sweden does look worse compared to its neighbors. We probably need to compare numbers when those countries went through the current wave.