I can't think of an instance where this is true for normal people. I can see an untrained 250lb person beating a 100lb one-armed boxer, but outside such extreme disparities, training >> innate ability, at least in my experience.
Sure is a good No True Scotsman you've got there. And I'm not even sure you'd be right ignoring that; recall that sports like boxing and MMA separate people into weight classes that are ten pounds wide. In other words, those sports think that, within the bounds of "professional", there is no amount of innate ability or training that can balance out a 25-pound difference in weight.
But even if you were right about reachable levels of ability, you fail to realize that the problem is less about the maximum reachable level and more about the ease of reaching a competitive level. Sure, most people can train up to run a marathon. But some people will take a year to do that and some people will take three month. And that kind of difference is crippling. Trying to get a degree in a one-year skill will cost you more in time and stress than trying to get a degree in a one-month skill, so much more that you may be out-competed and fail or simply collapse under the increased strain.
Furthermore, when looking at Real Life, it's not just about whether you can Get Good at a single skill that you can't choose. It's about how good you can be overall. It's impressive when a 100lb one-armed boxer beats an untrained 250lb person through pure skill because it indicates just how much time that boxer must have spent training to do that. But do we think that the "untrained person" sat on their ass that whole time? No. They spent that time playing chess. And as a result, while the boxer trains their ass off and has a fantastic day and somehow, against all odds, manages to beat the untrained person in a boxing ring... if they squared off across a chessboard the "untrained person" would casually style all over the boxer in between rounds of candy crush.
So yes. Training >>> innate skill, more so for some skills than others. But don't let that make you think that genetics are fair.
That's actually a bad example. UFC got its start with the spectacle of watching comparatively small Royce Gracie beat fighters with significant weight advantages who didn't know how to grapple.
There were some really extreme weight mismatches in 90s MMA: http://www.espn.com/extra/mma/news/story?id=3513974
I was more thinking outside the top 1% of any particular skill, for example when you're hiring a designer or sales staff in a normal company (as in, a not-1% company, such as a refrigerator manufacturer or something).
I'm willing to concede that if you're looking exclusively at top 1% or top 0.01% candidates, you may profit best by taking their innate abilities into account, but if you're trying to find a top 80% or top 70% candidate (if you're trying to play moneyball with your organization or something) I personally would weight the depth and breadth of experience most.
The NFL has 32 football teams. Any quarterback outside the top 10 or so is considered 'bad' by most people. Assuming each team has a backup quarterback, out of the 64 'best' people in the world to do that job, only the top ten are so are safe from being called 'bad at their job' on any given Sunday.
There's also a story about a UFC fighter who went 0-3, and people called him a terrible fighter. Someone from his hometown mentioned how he was the toughest guy in town and one day beat up 4 guys and 5 cops at a bar all by himself, and he was only a 155lb fighter.
EDIT: I think I may have uncharitably read your comment as being argumentative instead of informative.
I also knew an incredibly good 97lbs (44kg) wrestler. He was technically much, much better than me, but I could throw him around like a rag doll so I always won.
With weight comes strength. Any competition that rewards strength but does not penalize weight will end up dominated by heavyweights. Westling is particularly brutal as weight itself is beneficial for inertia.
Really? This runs counter to what I've heard from BJJ and other martial arts practitioners -- that a trained fighter could beat an untrained fighter in a fair fight (ie. no weapons, eye gouging, etc) using technique any day. You're saying that doesn't hold for wrestling?
What? Of course there is. Just at that level, the competitors are all training at their absolute maximums. There is no additional training on top of the world-class training they do that will balance out a 25-pound difference in weight.
I guarantee you a 120 pound (I'm ~145) MMA fighter can kill me with a well placed punch faster than I could even tickle them.
It depends on what you are doing but sometimes people are just wired for something better than others. But everyone can almost always get much better with training.
I can't. My money would be on the trained boxer every time. The untrained one will be slow and will leave an opening right off the bat, boom, one punch and he's done.