Don't compare countries, compare cities/regions. The Stockholm area is hard hit but e.g. the Malmö area fared much better. This isn't because of a difference in strategt but because the initial outbreak was smaller and later, so they had time to take action sooner. When Stockholm realized the problems in elderly homes, many of them already had the disease.

> I'd say it's safe to assume that at least 80% of Swedish deaths could have been avoided with a conventional approach.

What do you build that assumption on? Comparison to other countries, thinking "they have 1/4 the deaths and strategy X so if Sweden had strategy X they would have 1/4 the deaths"?

Half of the deaths were in elderly homes, and they could perhaps have been avoided with a different approach. That's the big failure. Old people who don't have care in their homes or live in elderly homes (e.g. retired healthy people) have been in full "lockdown" just like in most other countries.