"This article really is saying that kids don't need to learn math, because they can work in a factory instead. They don't need to learn English, because they can swing a hammer instead. They don't need to learn history, because they can wrench on a car."

The article says none of these things.

"However, I don't see the connection between the college track and the decline of these trades classes..."

Um, the connection is more kids following the college track, and fewer attending trade classes. Unless you expect kids to simultaneously pursue both, I don't see any excluded middle here.