No, the USA is not a meritocracy.
A meritocracy can only exist when it is subjugated to real freedom. For real freedom is required to systematically detect and explore all of human capacity and ingenuity that can contribute to the strength and integrity of our evolution. Not the oligarchic implementation of freedom of today that values only a monism of freedom and therefore severely restricts the aperture of merit.
Our exclusivity of freedom leaves a quarter of our children in the US to grow up with virtually irrecoverable mental disabilities stemming from poverty (15.8% in extreme poverty). Our freedom also weakens the immune system of 70% of Americans with an addictive dependency on prescription drugs, with $379B spent on anti-depressants. Our freedom also drives 69% of Americans into obesity with staggering medical costs as its ill-formed reparation. Clearly, our implementation of freedom does not even do justice to ourselves, let alone can justifiably serve as a model for the world. We can and must do better than that.
The merit of our next little Einsteins (or other meritable contributions to human evolution) may well be hidden somewhere in the fallout from our exclusivity of freedom, with the dangerous consequence of never being discovered.
To create a meritocracy, we must free freedom, by turning it from our flat, one-dimensional shoehorn of freedom into a relativity theory of freedom that can encircle and embrace the diversity of the world.
To start, we must define the basic tenets of freedom: The Paradox of Freedom.