Like you said, working at a Startup in the Nordics is considered risky, which doesn't make sense at all. Like the article underlines, Nordics countries have a insane social safety net, that even if your company fails, you're no where near as fucked as if the same thing happened in the US for example.
Yet, comparatively a very small amount of startups come out from the Nordics. Yes, Sweden has some, but if welfare = more startups were true, Denmark, Norway, Finland should all be top startup countries.
What I actually believe happens, and this is backed by personal experience, is that this safety net actual promotes doing nothing. Nearly all the gains/positives outsiders see of the system are wasted on the actual habitants. Nobody here thinks for a second longer about healthcare being free. It's taken for granted. So no, I don't think this is the reason for Sweden's success.
(Sorry for going on a tangent! Just wanted to write some of my thoughts)