The "genius" view of excellence is that talented people have a genii inside them who does the actual work. Some people have talent, others don't, and the talent carries them to greatness.
The Mundanity of Excellence, by Daniel F. Chambliss, makes the fascinating argument that excellence is not the result of an inner "genius" or an inner "talent," but rather that excellence, talent, genius is just the result of specific physical abilities and specific, learnable practices; that the required physical abilities are much more common than excellence is; and that the learnable practices are typically both prosaic and within the range of what many people could do if they chose to.
Excellence is qualitative, not quantitative. It results, not from doing more of an old thing, but of doing something new.
Performance is not on a continuum. It is in discrete levels. The big improvements occur in moving up a level, and one does this by adding or changing knowledge or behavior. Each performance level transition is made by identifying the specific changes that will get you there and then practicing specifically those, deliberately, until they are automatized. Can one skip levels by identifying the practices of the best in the field? I don't know.
One can make substantial gains in efficacy and productivity with less than a linear increase in time invested, just by doing better, not more, actions.
The high-achievers make performance mundane. They practice competitively, or under pressure, or otherwise make the high-stakes moments ordinary.
Chambliss marshals a lot of evidence to support his argument. I don't know if it holds for all cases, but it appears plausible across a wide range from sports, through music, and business management. What about a case such as Feynman, whom Bethe described as a "magician"? Possibly even there, because Feynman appears to have invested a lot of energy into improving the mental tools he had.
How does this relate to the Japanese idea of continuous improvement? I think it relates by identifying that the process of continuous improvement must be carried out qualitatively, by identifying inferior materials or actions that must be replaced by better ones.
How does this fit with the idea of convex rewards, where specialization pays off? It implies that I have a choice of how much I am willing to trade-off time spent in any domain versus the results. But, whatever the tradeoff I choose, I will increase my productivity most efficiently by following the ideas in The Mundanity of Excellence.
How does this relate to the idea of a Growth Mindset? Directly. If ability is not something that one either has or doesn't, now and for all time, but is potential actualized by learning knowledge or specific actions through practice, then the growth mindset accurately reflects this process.
In The Talent Myth, Malcomb Gladwell argues that rewarding people for having "talent," as opposed to character or actual accomplishments, is destructive.
John Allison makes a similar point on pages 38-40 of The Leadership Crisis and the Free Market Cure. Successful people are not more intelligent than others. Rather, they have two traits: They learn from their mistakes (growth mindset). They live their lives in focus (paying attention, being honest).