This article feels like a "wet streets cause rain" kind of thing.

I think there are two factors at play beneath this:

1. Your expectations of yourself. If you grow up with studious and career oriented friends and family, you expect that of yourself. Same when you grow up around enrepreners. On the other than there are social groups that have the attitude roughly "I work a random job until I get fired" - if that's the subculture you are brought up with, that can steer your own life too.

2. You self select your friends. My highschool had a mix of poor but motivated immigrant kids, and just like "bad" kids. The two groups didn't mingle, one ended up in the 1% by and large and the other group is in jail or on welfare. So you could say we did better because we had friends who ended up better off but I think it's the other way - we associated with people who are on our trajectory.

"Who you know" is important - but the first job I got through a connection was at age 45. Everything before that came from who I am not who I knew, but who know is shaped by who I am (ie I wouldn't have had the connection that got me this job if the guy hadn't known he as a high performer to begin with)