MO(S)P 1999 here. There's a huge "Shit Happens" factor. One bad decision or major health problem, or just a loss of interest, and you're on a different path an

MO(S)P 1999 here. There's a huge "Shit Happens" factor. One bad decision or major health problem, or just a loss of interest, and you're on a different path and it's hard as hell to fight your way back. Take that out 20 years, and you get the high fall-out rate. It's not that a lot of people fall off "the good track" for one reason; it's a bunch of reasons that affect small numbers of people. Success is also hard to measure at an individual level. If you're 35 and making $130k as a full professor of mathematics, you're a star. If you're a consultant making $130k working specifically on what you want to work on, you're a success. If you're still a non-shot-caller making $130k at a Silicon Valley company, at 35, then you've failed. We don't really know how people are doing, though. The "web developer in Boston" might be able to pick his projects, or making a lot of money.