I'm arguing that it's not what skill you learn, but rather that you did. You moved past something being new and exciting, got to the point where it was frustrating and boring, and you kept going anyway. I'm now wishing I hadn't use a computer as my example because I still feel like you're taking the wrong lesson from my anecdote. I don't credit my childhood computer use for my successful career as an adult. I credit my (forced) single-minded focus, where giving up was not an option.
In this story, my siblings-in-law never knew that it gets easier, never knew that there is a plateau you can overcome, and never made it to the other side. Because they never had to. It's a story about not giving up, not a story about how everyone should learn to use a computer.
You can be the most dedicated piano player, but if you later decides to channel that dedication into e.g. writing you are very likely to be struggling anyways. So now you are essentially in the same boat as everyone else.
Young people are mainly struggling because education, housing and long term careers are competitive and costly. Of course dedication can help with being successful in almost any sense of the word. But overall it is very likely overshadowed by other factors as e.g. your position in the housing market.
How many people who could afford a mortgage in a major city in their early twenties, by any means, are struggling with their lives today? Certainly a few, but surely a lot less than those who don't yet have a stable home in their thirties.