The only thing I disagree with is that it's "bizarre." I think on average people have 6 careers in their lives. And people change jobs every few years as well. It's just a part of life to improve or change what you work on and there is no shame in that. I've worked in the bay area for almost 4 years at the same company and I think about changing things all the time.
That's a fairly tech (and probably Bay Area) view of the world. I've been ~10 years or longer at three separate companies and I know tons of people in the same boat.
