I don't think this quite captures the situation. Companies aren't complaining about a lack of credentialed developers; they're complaining about a lack of competent developers.

In 2000 there were far more people graduating with computing degrees than in 1995; but the average quality was far far lower. The people who suddenly found that they couldn't get jobs when the dot-com bubble burst? Most of them didn't belong in the industry in the first place.