Because...yes. So much yes. Even had this person engaged in crime ('to feed his family!'), but still come out of it on top, we'd be saying "see? Even with those slip ups, he did the right thing most of the time and came out on top", but then we turn around and three strikes, lock someone else up for decades. And we don't know the people who failed, despite doing everything 'right', who died homeless and malnourished.
This difference between individual advice and group-level policymaking (mentioned elsewhere in this thread by chmod600) accounts for a lot of talking past one another in political debates. They are two totally separate levels of analysis.
To be clear I'm not saying there isn't a level of difference in talent or work ethic; what I'm arguing is that viewing the world that way makes for terrible government policy. When someone says something like "welfare makes people lazy", they are making the mistake you are. Somehow the imaginary "real life work" is directly correlated with effort, but actual finance jobs are not.
There are successful companies and products that don't seem to have a lot of either behind them beyond the initial work to find a successful niche, that they've leveraged to great success. And companies and projects have failed despite having both of those because of circumstances outside of their control.
Just like people, companies are products of their environment. Why -doesn't- someone work hard? Or make the right choices? Because either of their environment, what they've learned, or because of who they were born as. Neither of those is under their control. And even if they do, and it doesn't pan out, why didn't it pan out? Again, factors outside of their control.
Perhaps there are some fund managers out there that are just like "Yep, it's a rigged system, I'm going to be the one getting rich off rigging it", but I haven't met one personally yet.
On a national or even global scale I try to avoid generalizations like this because trivially they don't lead to good policy outcomes. It's almost a little like stock picking. If 5/100 hedge funds make a positive return over the year, my first thought isn't "the other 95 refused to work to better themselves".
It's easy to understand this with hedge funds, but people commonly make this mistake when talking about human beings. You wouldn't be taken seriously if you said those hedge funds lost money because "they refused to work hard". I feel most people are the same way - I don't think any rational actor refuses to better themselves, rather it is a fallacy we tell ourselves to explain why things the way they are. I've seen plenty of "hard working" people relegated to poverty because their kid got sick.
Finally, the best solution is not to focus on individual funds, but on the index. Providing a better baseline for all companies leads to a better overall index and having a strong economy involves having a section of it the "wastes" a lot of money investing in the in the future.