This post below is to a BBC article about a novice being given special lessons to test the idea that with enough 'deliberate practice' (i.e. quality coached hours), very high skill increments are possible.
This is a fascinating question. Can 'anyone' become skilled? Or do you need to be 'special' in the first place. My take is .... to stay at elite level ..... if you have skilled people in the first place, then what differentiates these people are their commitment to hone these skills, and polish them too, with mental skills as well.
This 10,000 hours idea came from Chase and Simon's (1973) work on chess grandmasters, who were said to study for about 10,000 hours to achieve elite status and aqure a library of 'chunks' that they can use to read a board effectively to aid decision-making. Subsequent study by others, such as Ericcson (1993) saw 10,000 of deliberate practice being a common theme to the pathway of excellence in any domain - music, sports etc. This idea motivates this article in the link, above, except there are short-cuts being made as 10,000 is quite a few years even if you train everyday.
I think you can take any raw material and coach someone to a solid excellent standard. To achieve elite standard and maintain that may need something else ... but what? Desire: temperament, continued commitment to excellence, genetic programming, perpetual funding, good support network of peers and coaches ?
This is the YouTube video from that BBC article. They posted monthly progress videos.
This is the associated web page of the project. Can't wait to see the book. This whole question has implications for all learning, I feel. I think the top 250 goal was ambitious but agree with the BBC web page that table tennis is the wrong sport to choose, rather than the whole project being flawed.