[subsystem]

IKEA opened their first store outside of Scandinavia in 1973, H&M in 1976 and according to wikipedia Tetra Pak had financial troubles until they became successful in the mid 1960s. Of course Sweden had a major advantage in that its infrastructure wasn't destroyed in WWII.

[mongol]

That's true. But I think while the "infrastructure" argument explains a lot why Sweden has done well "in average", it does not explain why there are more billionaires than average. I think that is more due to individual drive and entrepenureal spirit of Persson, Kamprad and Rausing.