I think the problem is that there are some unteachable intrinsic talents necessary for programming, and many people irrevocably commit to getting comp sci degrees before discovering that they can't be taught to program.

I think there are failure modes from the curiosity-stopping anti-epistemology cluster, that allow you to fail to learn indefinitely, because you don't recognize what you need to learn, and so never manage to actually learn that. With right approach anyone who is not seriously stupid could be taught (but it might take lots of time and effort, so often not worth it).