I sort of did a similar experiment from 15-35 with boxing. Trained a lot and became pretty competent. But to get to the top hard work is not enough. You also need talent. There are people in the gym that had speed and strength without any training that I couldn't reach with daily hard training. But I think doing this was probably still the best thing I did in my life. Doing something that seems out of reach and then…
I'm inclined to wonder if they were lucky & came with it, for whatever reason. Like, they happened to grow up playing basketball and shoveling dirt, so they have years of formative training already.
I heard an interesting hypothesis once about ski stars- basically, that many pro skiers today had just the right foot & shin geometry as kids such that ski boots fit really well. A kid whose foot is NOT a great fit for the boots, might have plenty of latent skill & ability, but nobody custom-fits boots for kids. That's not to denigrate the pro skiers today, just to say, everyone comes to a sport with a different background, and having certain lucky prerequisites help you stand out right from the beginning.