You didn’t make it as a concert pianist? You must not have wanted it that badly. Societal inequality is thus justified on the grounds that anyone who is willing to put in the requisite time and effort can succeed and should be rewarded with a good life, whereas those who struggle to make ends meet are to blame for their situations and should pull themselves up by their own bootstraps.
If we acknowledge that people differ in what they have to contribute, then we have an argument for a society in which all human beings are entitled to a life that includes access to decent housing, health care, and education, simply because they are human.
Now I feel bad for the dude who wanted to test the 10k hours theory by becoming a pro golf player. He started late in his life and was around 7000 hours in practice last time I checked.
If he enjoyed it, then does it matter?
Seriously. There are things I'm not that good at but I like doing. I like playing rhythm when a song breaks out. I'm not a very good guitarist, but I can pick up quickly. I can keep a beat so others may riff. I just want to keep a rhythm going so a room can fill with sound.
A person can have inherent skills and passions. They don't necessarily meet. I knew a kid in kindergarten and first grade that could draw like a teenager. He was, in contrast, into science. So that artistic talent got a major boost early but may never have gone further, while the interest in physics had the passion thus the investment.
Sometimes we're good at something but don't care about it. If your society upholds X and you suck at X, you may still be hung up on X and be mediocre at it or good at only the aspect of it that went with something inherent to you.