Super-prodigies have appeared before. For example: William James Sidis. There is a danger for people of this level to burnout young or become so frustrated in dealing with the rest of us (comparative) dimwits that they withdraw from society and become obscure figures like Sidis. That Barnett has been diagnosed with Aspergers makes me think the latter might pose a particular challenge to him.
Einstein actually wasn’t much of a prodigy, all things considered. He famously drew the scorn of one of his undergraduate mathematics professors (Minkowski, who later elaborated on special relativity). His four ground breaking papers of 1905 (on Brownian motion, special relativity, the photoelectric effect and mass-energy equivalence) were published when he was 25 or 26 years old. What set him apart from his contemporaries was his clear thinking, physical intuition and boldness. The mathematical tools at his command were very basic in the beginning. It wasn’t the math his peers had trouble following at that time, it was his nerve to challenge long-held assumptions.
Now a real physics prodigy – and one who “held it together” and achieved a distinguished (if isolated) carrer – was Julian Schwinger. But he’s hardly a household name now, is he? ;)