Pro sports is full of natural talents and the top guys are the ones who also work hard in addition to their natural abilities.
I can run a 10.5 after a lot of training, so maybe it's my ego talking here, but I refuse to believe this! I think you must just not have been aware of the training this person did. If they could really run a 10.5 in high school with no training, then with minimal effort they could bring their time down enough to qualify for most any country's Olympic team. A 10.5 100m is good enough to win the high school state tournament in an average US state.
> From time to time we would have some new guy come who clearly didn't know anything about boxing or fighting. But within weeks he would learn and get better than almost anyone else in the gym. He would be faster and punch harder.
These people must have had prior training in other sports. Once you've done strength, agility and speed training and have good coordination, it's easy to pick up another sport.
I think most of that "natural" ability is still down to practice. Tiny innate differences and advantages push people in certain directions, which means they practice those more (through play, to start with), and pretty quickly there are big apparent differences.
If genetics didn't play a meaningful role in athleticism, we wouldn't have evolved it. But even if that was true at some point in history, that would only be temporary, because without selective pressure, genetic drift would move the population to some point where there was selective pressure.
Obviously environment plays a role, with climate giving kids in California more practice time, or the annual cut-off date in team sports affecting who's in what age group.
On the other hand I am much better at software development than a lot of other people with the same background. It was always easy for me to comprehend things and then I also put in a lot of work.
This is not to say that practice isn't the most reliable way to achieve gains (it is!), but some 'just get it' and have ability (either musical or dextrous) on the instrument that most take a lot longer to achieve.
Outside of super-rare outliers, I don’t personally believe that anyone is born with natural talent for anything. When someone is highly skilled at something, I will assume that they spent tons of obsessive time learning and practicing rather than that they tried it one day and found they were magically good at it.