"And even perfect practice will not help a person who is actually tone deaf."

Worked out well enough for Beethoven, Smetana, and Faure.

I always think "perfect" meant "intentional" in that just going through the motions doesn't do the trick but actually being thoughtful about what you're trying to achieve and trying really really hard...

there's a difference between grinding out technique and actively confronting the your weaknesses, especially those that have nothing to do with technique e.g confidence, ego etc. there's also the question as to what percentage of practice time is spent trying to replicate the masters as opposed to deepening your understanding of the underlying mechanics or developing intuition. you learn more from a poor creation than a perfect copy.

as for talent, i still think schmid summed it up the best 'Don't bother about whether or not you have it. Just assume that you do, and then forget about it. Talent is a word we use after someone has become accomplished. There is no way to detect it before the fact... or to predict when or if mastery will click into place.'