[calciphus]

Because it is good for workers, and therefore workers who value themselves (or more specifically, understand their value to businesses) will want to live someplace where their rights are more important than their companies.

For example: non-compete clauses are unenforceable in California. This makes it "unfriendly" to businesses, but much more appealing to highly skilled workers who don't want to be boxed out of their industry for two years just because they dislike their job and want to quit.