While I agree those aren't unimportant I have come to a somewhat different conclusion after spending some time outside of Sweden. Most people in most places are just busy doing other things. I don't think Stockholm's success is so much what was, but what you didn't have to do.

In the early 00s it was relative easy to become "high middle class". Rent controlled public housing was available so you didn't have to spend $10k-$100k to have stable housing. Public transport was in a good state so you didn't have to spend $5k-50k on a car. Education was available but not generally considered necessary. Mostly cost-free universal health care was the norm. Even marriage wasn't the norm. This meant you had pretty good chance of having your life relatively sorted by your mid-twenties and therefor a much lower cost of doing something else. Compared to other countries where most people are busy trying to attain such things for far longer.

That other countries didn't have the same success because they didn't have good enough broadband is a somewhat safe explanation. Most countries didn't even try, and still don't try, to get good broadband because success is mostly seen as something private.

This is of course somewhat controversial not just abroad but in Sweden as well. As the Stockholm of today would do quite badly by these criteria.