I don't agree at all. In this market it benefits technology workers to be at-will. You can get a great job offer and literally leave your job the next day. This drives salaries up overall and means companies need to work harder to keep people.
Compare that to the UK, where it's standard practice for a senior dev to be stuck with a 3 month notice period. I had a hell of a time getting out of a bad situation when I first moved here as a result.