If they really never did (did anyone really search all the following numbers to check if there was something?), the reason why ranges from just other priorities, not seeing that as a big deal (it's not unlikely that they'd have a larger record of uncorrected mistakes in many areas of science, specially out of actual scientific articles), and also possibly perhaps to avoid public embarrassment. Pride, difficult in saying, "sorry folks, I didn't quite get what he said at the conference, or I didn't express it clearly enough, he really didn't really mean that small changes don't accumulate at all, like it could be understood from what I wrote, but rather that they don't accumulate at an even rate through evolutionary course of a lineage, there being periods where small modifications accumulate comparatively much more rapidly. My bad." This retracting could also illustrate the "no big deal" alternative, anyway. Perhaps to avoid creationist pseudo-polemic. "Editor of prestigious SCIENCE magazine CONFESSES he has a poor grasp of the fundamentals of evolution, making a total mess of what so-called scientists really say. Can we really take «scientific» publications with the same certainty as the words of God? Are these men really infallible, like Jesus?" He couldn't imagine that now, 30 years later, the "debate" around this "issue" would be barely different.