This sounds like a wonderful idea but I'd love to hear some stats on how this specific time-off fares for would-be startupers. The article mentions a few successful start-ups but it's unclear whether these came about as a result of the time-off or if they resulted from someone just pursuing them full time. Not knocking the idea either way, just would love to see data on how many new companies it's helped create.
From my experience people are more likely to use this for studying, trying a business idea (not the HN meaning of startup) or extended travel. Startup I imagine is an outlier in what its used for.
It lines up well with the very advantageous student loans (for living costs, university is free) for studying and lets people try their hand at going through higher education wothout throwing their job away.
I mean... most startups fail. Surely that's no less true in Sweden than elsewhere. If you want statistics, I guess you'd measure this in terms of successful exits or revenue or equity size or something as a fraction of population or GDP or workforce. But at least anecdotally (c.f. Spotify/Skype/Mojang) they seem to be doing pretty well.