I think you underestimate the ability of some people to pass classes without learning anything. I met an engineering student who had somehow passed a tough, high-quality technical writing class and yet could not write a coherent sentence, let alone a useful paragraph. I suspect that he cheated his ass off in most of his classes.
You know, I feel no sympathy for such people. If the reason they don't know how to write "well-enough" is because they cheated their way through college, then they deserve whatever lack of career opportunities they find themselves in.
