Anthropic Unpaired Negatives

Someone asked me a few days ago why we have the word gormless but not gorm or gormful. Wouldn't it be useful to say that someone is so gormful? I'd just discussed this very word back in May, and it's just one of many unpaired negatives in English. Some others are: ruthless, uncouth, disgruntled, immaculate, and inept.

As usual, Michael Quinion has some required reading on the subject, the summary of which is that the positive forms for whatever reason go out of fashion and so we get left with the negative. Occasionally someone will reconstruct the positive form, but generally the negative forms remain the more popular.

But why are these words inherently more useful, or at least more fashionable, and why does it only happen with negatives? Of the former question I have no idea, but I wonder if the anthropic principle can explain the latter. For any given positive-negative pair, the negative is usually formed by adding a prefix or suffix to the positive. So when the positive disappears, we still have it retained in the negative form. If the negative disappeared, on the other hand, we'd have no trace in the language itself that it ever existed. So the question becomes: are there as many archaic and obsolete negatives?

Cite: Palmer, S.B. (2005). "Anthropic Unpaired Negatives", in: What Planet is This?
Archival URI: http://inamidst.com/notes/unpaired