ETA: Okay, I've recently found out that this quote is not Vonnegut, although he did write something similar to this in a letter to schoolchildren. That letter was posted to three--ring's blog with her commentary posted below. Her commentary was copy-pasted to Facebook as being written by Vonnegut, and it's been passed around that way ever since. Proof here.
I'm fixing this post with proper attribution. I did do a quick web search before posting this, but apparently it was too quick. Bleagh.
I think that almost anybody can become proficient, but talent is something innate. We aren't just blank slates. We are naturally better at some things than others. There have been numerous examples of prodigies who showed amazing skill at a very young age, despite having relatively little practice. For example, Mozart was taught how to play piano from the age of four and was able to compose pieces at the age of five. Many parents have tried to get their small children to play musical instruments from a very young age, but most of them have not been able to produce new Mozarts. Of course, Mozart and other prodigies practiced a lot, too, but others who practiced just as much, if not more, got nowhere close to their skill level.
Now, the reason I said almost anybody is because it makes sense to me that if there are people who are talented, then there must be the opposite, people who have anti-talent. There are people who are so tone-deaf that they'll never make good music, not even if they practice every chance they get. However, talent and anti-talent are at the ends of the bell curve: most people are somewhere in the middle, and if they practice enough, they can make something which is adequate, if not good...and, occasionally, even something great.
I respectfully disagree with almost everything you said. If you can teach someone art, which you can, then you can teach someone to "have talent." There are people who refuse to learn because they don't like it, or don't want to, but you can be taught just about anything.
Take Mozart from your example, he was taught to play by someone who didn't hold him back or try to stop him, that is a gift right there. What if everyone's "talent" is just being free with what you enjoy and no one is stopping you in one way or another.
Let's not even go into who decides when you have talent or not, because it's trendy and there are taste makers.
I have two questions for you.
Do you believe that everybody is a blank slate without variation?
Mozart learned to play at 4, began composing at 5, and wrote his first symphony at 8. Do you think that every child is capable of this?
No, but being the best and being "talented" are 2 different things.
No, not every single child, but I bet there are lot more than we realize. He was nurtured as well, obviously. I made up melodies in my head as a child, but I didn't have access to a great teacher and a piano.
Which brings up something else, how many children are brought up with musical instruments around them that are serious instruments and not playschool quality? How many children that want to explore music aren't allowed to? If I had a child surrounded by accordions and that's what they learned to play on and compose music, don't you think the response would be different than mozart's piano?
I'm not saying I'm right 100% of the time, there are going to be mechanical issues with people's bodies. I'm saying that most people can get really talented (not the best ever) if nurtured and allowed.
Note: I apologize if my tone sounds antagonistic, I truly mean this as a discussion.