How much did practice actually explain? A 2014 meta-analysis looked specifically at the relationship between deliberate practice and performance in music, games like chess, sports, education, and other professions.
For some things, like games, practice explained about a quarter of variance in expertise.
For music and sports, the explanatory power accounted for about a fifth.
But for education and professions like computer science, military-aircraft piloting, and sales, the effect ranged from small to tiny. For all of these professions, you obviously need to practice, but natural abilities matter more.