Sure, for certain individuals the US, or Europe, or much of Asia would provide a better life.
But compared to how things were in the past, the US has changed for the worse.
I'm a white male, so I can't really complain about being mistreated in the sense you're mentioning. But in talking to many people, and in my own experiences, there's a sense that the "meritocracy" is increasingly a falsehood based on survivorship bias.
My own sense is that this is largely driven by increasing income inequality, coupled with or driven itself by monopolies and rent-seeking behavior across many many domains. So a smaller and smaller pool of money is going around to those who are able and willing, and a disproportionate amount of it is going to a smaller few who either game the system, or who are willing to tolerate abuse.
Part of what the article is referencing, I think, is a shame among Americans to say this, because it's labeled as sour grapes or something. I also think part of it is a sense that admitting the system might be broken is actually less optimistic because it amounts to some admission that you don't have agency. But these seem increasingly untenable as positions to have.