> Just because I can't estimate a task accurately doesn't mean I can't do it.
Most programmers could ultimately do anything... if given enough time.
But if they're going to do it professionally, you expect them to have some prior experience so they can do it somewhat efficiently. And if they have that experience, they should be able to estimate.
So yes, being able to estimate and being able to do (with reasonable professional efficiency), do tend to correlate, of course.