I do agree that a safety net is a useful thing to have.

But I disagree with the impression from your post that a safety net would have been the preferred solution to this merchant's woes. It would only keep him slightly afloat, compared to being careful about his business, where he could have kept a significant portion of it.

The line between being careless and blaming the victim is blurry, so I'm not going to discuss it.

However, building a successful startup is fundamentally different from running a sustainable business: in the former case, you deliberately make a high-risk, high-reward bet, while in the latter you want to take only enough risk to keep going. I had the impression that the story was about a business trying to be sustainable getting ruined.

Yes, it's a high risk strategy. Most people are more risk averse than that and don't follow this sort of strategy. Thus, they do not become bankrupt, or rich, in the same way as this man.