The Gladwell piece actually does a better job illustrating the point, I think.
Gladwell effectively claims that success in life is due in part to finding the right opportunities at the right time, and the networks you get at Harvard and Yale (and many other potential places, Gladwell doesn't focus on universities the way this post does) provide you with a mechanism for finding those opportunities. And this is "opportunities" in the broadest sense.
I'd believe that if you and everyone you know works low-paying service jobs, that it's then going to be harder to discover opportunities for pursuing passions and career advancement.
Gladwell effectively claims that success in life is due in part to finding the right opportunities at the right time, and the networks you get at Harvard and Yale (and many other potential places, Gladwell doesn't focus on universities the way this post does) provide you with a mechanism for finding those opportunities. And this is "opportunities" in the broadest sense.
I'd believe that if you and everyone you know works low-paying service jobs, that it's then going to be harder to discover opportunities for pursuing passions and career advancement.