The article isn't about entrepreneurs, which are an entirely different type of person that makes different kinds of mistakes. An entrepreneur isn't afraid of making mistakes, regardless of his place in the social order. That's why he's starting a company instead of working for a bank.
The example given in the article was: "two analysts at a prestigious financial firm". A "prestigious financial firm" is not a startup, and while networking is important, it isn't the same networking/hustle that a entrepreneur engages in.
I don't think it would be possible to disagree more. Connections are not at all necessarily required for startup success.
I am speaking here merely from an anecdotal and firsthand perspective, but all it takes is one data point to refute the claim that condition A is necessary for outcome B.
Having good connection is a necessary (but not sufficient) condition to identifying customer pain points, finding VC money, doing sales, etc.