Speaking of CalTech:

In the states, I once met a guy who was married to someone I knew. He was a really cocky sob, and as usual, it turned out that after his degree in China or Russia, this man was employed in Hongkong which made him feel so important. From there, he moved to the states. His wife was a very decent lady and so one day I went to have a dinner at his place. He kept on talking and talking. He was a civil engineer, and after awhile, not sure what I should talk him about, I finally asked him whether he thought of going to any graduate school. Then this is what he said. 
  " I meet professors of MIT, Berkeley, Stanford, CalTech all the time. In fact, they have been asking me to join there PhD program all the time.I don't want to. I am a boss at my office, there are 42 people working under me, and the company worth 4.5 billion dollars can't be run without my support."

In one form or another, I still frequently meet our people who tell me that (i) they could get into any school, but are not choosing to do so. (ii) That they are the lynchpin of the firm they are working on. Not sure how many of these people are correct.