Confidence I agree with much you've said. What saddens me is that I believe the NC levels within our system/its linear structure often stifle potential. You identify internal motivation as a predictor of future success but how many switch off early as for various reasons things don't come as quickly to them as they perceive they do to others?
Certainly agree about the straightjacket of NC levels. And how many switch off too for the opposite reason - that schools hamstrung by that system are not able to present the subject to them in a way that would engage their early readiness for it?
I'm certainly not trying to suggest here that everybody is genetically the same. But I think the problem is that when people describe someone's advanced ability or speed of learning as being due to "talent", they don't actually do so based on any evidence. There may be some general evidence from what we know about genetics, but invariably they haven't actually studied the genetic code of the individual they're referring to and found anything that sets them apart. My understanding is that attempts to do this with successful sports people for example have generally failed, and found that they have as much genetic diversity as anyone else.
So the talent hypothesis reads to me a bit like the First Cause argument for the existence of God - something basically made up to fill the gap in the face of an overly intimidating number of variables. Science hasn't completely ascertained how life came about and probably never can now, so we'd rather just make something up than admit we don't know.
This is kind of understandable when you look at what contibutes to people developing skills and abilities. First of all there is the contribution of DNA itself, which is far more complex than popular understanding often supposes, with many different genes contributing to the same effect, and likewise single genes often contributing to multiple, highly disparate effects. There are genes which "switch on" in response to environmental stimuli, or just switch on later in life, and so on.
Then there is the multi-facted nature of "skills". One of my pet hates in my own field is how people refer to children as being "musical" or "unmusical". What does this mean? The skills needed by a jazz drummer are very different to those needed by an opera singer, and my experience with young children is yet to suggest that the orientation towards these, and many other possible "musical" skills, is in any way connected. I have taught enough people with fantastic voices and very clumsy coordination, or vice versa, to believe otherwise. Then to make matters even muddier, there's the fact that there are often many different ways to achieve even the same skill.
Then finally there is the role of environment, experience and particularly, parental emotional "nurture" in the early years. What happens to the person with the voice and the person with the coordination if they are both raised in an opera singing family who hate and don't understand jazz? Or if they are both raised by a professional jazz drumer who hates and doesn't understand opera? What happens to those whose relevent genetic components to achieve something switch on at the age of eight? Are they already put off the thing by then by pushy parents who couldn't accept that they couldn't do it at five? Or are they not exposed to the experience until they are fifteen, by which time they find others are much more expert than them and they can't compete? Or are they fortunate enough to find everything come together at exactly the right time?
I think in reality the number of possible combinations of all these variables must approach infinity. There will naturally be some combinations that result in strikingly quick learning or skill development, and some that result in striking difficulties. There's simply no reason however to postulate that that's due to some absolute genetic difference that can be considered apart from the other factors - other than that, like the First Cause argument, it's simple and understandable and has centuries of habit behind it.