Like it or not, even the more "manual" jobs are needed and will always be needed. Somebody needs to do landscaping. Somebody needs to run a dry cleaner. Somebody needs to fix cars. And no, not all of them legitimately require a college education.
A friend of mine told me once that he has two friends... one a judge and one a plumber... and the plumber makes more money per year than the judge. Sounds like the plumber made 'something' of himself to me.
When your pipes break, are you going to fix them? Probably not. Shoot, even changing one's oil in their own car is fast becoming a lost art.