Their main claim was that a particular test at the beginning of the course accurately predicted the outcome of the course in terms of their grade. Someone else mentioned that in the later papers, they say that their test is no longer predictive.

It's possible that people are enough more used to computers that some elementary concepts (like that the computer responds to simple cues rather than having any understanding of what you mean) are much more common, so those concepts aren't as useful for filters.

My model is that there is something (I am not sure what it is) that is necessary for programming, but we don't know how to teach it. Maybe it is too abstract to articulate, or seems so trivial to those who already know it that they don't pay conscious attention to it . (Maybe it's multiple things.) Some people randomly "get it", either at the beginning of the class, or usually long before the class. Then when the class starts, those who "have it" can progress, and those who "don't have it" are stuck.

The study suggests that this something could be: expecting the same actions to have the same results consistently (even if the person is wrong about specific results of a specific action, because that kind of mistake can be fixed easily). Sounds plausible.

Assuming this is true (which is not certain, as the replications seem to fail), I would still describe it as a failure of the education process. There is a necessary prerequisite skill, and we don't teach it, which splits the class into those who got it from other sources, and those who didn't. -- It would be an equivalent of not teaching small children alphabet, and starting with reading the whole words and sentences. The children who learned alphabet at home would progress, the remaining children would be completely lost, we would observe the "double hump" and declare that the difference is probably innate.

The disappearing of the "double hump" (assuming that the original result was valid) could hint at improving the educational methods.

Even with perfect education, some people will be better and some will be worse. But there will be more people with partial success. -- To use your analogy, we would no longer have the situation where some people are basketball stars, and the remaining ones are unable to understand the rules of basketball; we would also have many recreational players. -- In programming, we would have many people able to do Excel calculations or very simple Python scripts.

If consistence really is the key, that would explain why aspies get it naturally, but seems to me that this is a skill that can be trained... at worst, by using some exercise of giving students the same question dozen times and expecting dozen same answers. Or something more meaningful than this, e.g. following some simple instructions consistently. It could be a computer game!

Ok, I will.