I don't believe this stuff at all. Your average AP student has better study habits than Evariste Galois, and about a 0% chance of understanding Galois theory by the age that he invented it (19).
Deliberate practice seems to be very important in sports. And the modern regime of sports practice, where people specialize early and follow a strict regimen over years, produces results that leave earlier generations in the dust. Almost every athletic record is held by people alive today, and the best performance of 1900 would be considered amateur-level today in most sports.
The same is clearly not true in mathematics. The modern regime of math practice, which involves lots of schoolwork, homework, tutoring, and other regimented practice, has not left 19th-century standards in the dust. The achievements of Galois would still be utterly extraordinary today. The notion that sports-style "deliberate practice" is universally beneficial towards a vague notion called "expertise" is simply not true.
