Your first point is telling. Talent mobility has increased among young software developers. Dan Lyons was not a young software developer; he was an older employee on the business side of the enterprise.

It's possible (though: see game development companies for counterexamples) that abusive management of technologists at technology companies will be self-defeating, and that those companies will find themselves locked out of the talent market. But the story Dan Lyons is telling seems pretty well aligned with, for instance, reporting about Amazon's or Yelp's work culture: if you're not a young or elite technologist, management can in fact abuse you with impunity.