Did you read the article? He talks about how he got his goldman job as a result of a series of events that started with him happening to be sat next to the wife of a goldman employee.

Yes, I did read Liars Poker. I think its kinda funny that you question whether I am qualified to comment on his career, but a little bit of research shows he worked at goldman for awhile, wrote the book and has been a writer ever since. In other words, his success is clearly in writing.