And where did they go to school? Who taught Eric Clapton? Or Bob Marley? Or Mick Jagger? Or Muddy Waters?
yes, the julliard school can and does teach technique. But school never produces the next Mozart.
Mozart was indeed taught music. And he had at least 10,000 hours of practice under his belt before he produced anything of consequence. Read the book, Outliers to understand the fruition of talent.