To think the author's statement was intended to apply to every single person past or present is ridiculous. I'd prefer we continue using language the way rational people do, and just chalk refutations like this one up to pedantry.
Obviously the author was talking about the general case. The parent commenter's refutation cites one edge case, and on that basis declares the author's statements are untrue.
This is a huge time-waster in (almost) every public argument on (nearly) every subject and I wish people (not all people, only those who engage in this pedantry) would stop doing it. To qualify the relative scale of (almost) every single claim or assertion would make (many) articles unreadable (in my opinion) and speech so labored that (many) people would probably prefer to just not engage at all.
You are, of course, right. My story is meant to inspire and serve as counterbalance to the fatalist viewpoint in the original post.
For every one of you (or me, for that matter: I was born into a family in which few had graduated high school and grew up frequently going hungry in a single parent home and am now a well paid physics PhD holding data scientist and engineer) there are dozens (or more) of people who grew up in similar conditions and never made more of it.
There is substantial evidence in support of this thesis, from decades of research in economic mobility. Your story of success is only a single data point in answering this question.