In the book "Talent is Overrated" by Geoff Colvin, the definition of talent is familiar to everyone on here - it's "the natural ability to do something better than most people can do it." Colvin argues that the existence of "talent" is not supported by the evidence. Close examination of high performers show that the vast majority of them have a least one thing in common...a great amount of "deliberate practice", and not some innate ability that most people don't have. Now that practice may not necessarily be 10,000 hours like what's commonly cited (which would amount to 80,000+ miles), but a huge amount of it is definitely necessary.
I completely agree with this and am getting tired of people claiming that talent is necessary for young male runners to hit semi-decent times like a 4:20 mile at least once in their life. Like Sean Brosnan said, 4:20 is not that fast. Granted, no amount of training will turn an average person into an Olympian or even a sub 4 miler, but a totally average guy could definitely run a 4:19 by training hard (and smart!) enough for a period of many years if they had the motivation to do so. Of course, that means that 49.9......9% of the population would not be able to do it. That's why they're below average.
If you are so sure it requires talent, and you know cases that train perfectly, do high mileage with decent workouts and training plan/coaching, don't cut on sleep and eat decently, and so on, show me that data. Give me a case where someone did all of these things and plateaued at something absolutely terrible like a 17 minute 5K.
Show me Strava profiles, race results, preferably of many years of training where someone still doesn't run a respectable time and considers talent to be the only reason he couldn't get further. Or the so called "non-responders" as some of you said.
Don't use the small percentage of people that are either morbidly obese, disabled, female-to-male transgenders, etc.
GL, I'd be extremely surprised if you can actually back up your claim with real people.