And the very first comment, about Kerala, rings the bell for many of us, I think.
I do agree with some of the comments (there as well as in Hacker News) that a comparison of the US with other "immigrant" countries such as Canada and Australia (and New Zealand; what else? Israel is very specific) could be instructive. But it would require a separate article, I guess.
As a side note, the two discussions of this article (one, two) in Hacker News that I saw were of a lower quality than I have come to expect from HN. Maybe it is because the topic is not one where most of the HN readership has professional expertise. Or maybe it is the timing of the holidays.
Also, the title is unfortunate (The Ponzi scheme that works). I guess the only place where it could fit the definition of a Ponzi scheme is family-based immigration, where one immigrant can bring in more immigrants from the immediate family, but this typically stops after one iteration.