The really sad part of this journey is that most of those people, beyond youthful idealism, had no idea whether that dream was for them. Because there is very

The really sad part of this journey is that most of those people, beyond youthful idealism, had no idea whether that dream was for them. Because there is very little mobility into academia, MANY people land on the wrong side of the pond. You can't try industry and go back. One more difference is that colleges once wanted people with decades industry experience, and many older people saw going back to teach young'uns as a way of giving back. It's not just older people. If you're in industry, and want to pursue a good idea for 5 years where you don't have elbowroom, or in academia and want to try to commercialize something, you break your academic track. It's possible with tenure, but I find many tenured academics distinctly underimpressive by the point they've gone through decades of abuse to get there....