Why do you think *graduate* education is so expensive and so overrated?

I went to an Ivy League school this week to check some graduate classes in topics that I enjoy. It is fair to say that these were in vogue topics and that I have some decent in-the-field professional experience with them. Two things surprised me:

1. 75% of a class of 120 students were asian


2. The professor clearly did not have much clue about what he was talking about

So my question is: Why do people pay hundreds of thousands of dollars for this type of education that doesn't prepare you at all for what is currently out there.

Wouldn't it be muuuuuch better to work for free for a company instead of paying to train your brain with useless material?