"increase supply in college graduates while decreasing supply in workers of skilled trades. Thus, the latter would get to demand higher incomes (while the former would see theirs decreased)."

Even today some people are making the argument that college grads can't find good jobs. Wouldn't more grads make the problem worse?

I think some of those college grads should find their way into skilled trades. The trades may lack some of the sizzle, but they definitely result in jobs that serve a purpose.