For the lucid moments he has, which people would argue about the frequency of, Alex Papadimoulis discusses something similar to this in one of his site articles, providing what I think is decent insight on why they make it to retirement age:
FWIW, I think there's enough people in this audience that wouldn't be happy holding on to a job they aren't particularly interested in keeping up to date on, simply because they have the domain knowledge to make them "safe". I could be wrong though.
Huh, combine two elements in the article you linked, quoting:
* The higher-up the position, the longer the curve. Changes tend to occur much more slowly at the top. For example, a basic “refactoring” of a department’s teams could take well over a year to implement.
* The greater the skill, the shorter the curve. Ambition and skill go hand-in-hand, and ambitious individuals tend to want swift changes, and quickly lose motivation when these don’t happen.
* The larger the company, the shorter the curve. Large teams are generally not receptive to ideas from the new guy, leaving a large part of contribution (i.e. past experience) wasted. Furthermore, promotions are often based on tenure, not skill.
* The smaller the company, the longer the curve. Smaller companies, on the other hand, are more receptive to change, allowing one to contribute past experiences for a long while.
* The less skill-demanding the company, the significantly longer the curve. Not all companies need top talent. For example, the company who needs only maintainers of an ancient COBOL application might be best fit with curves that are closer to the value convergence."
Notice what happens when you're very skilled in a large company?
http://thedailywtf.com/articles/up-or-out-solving-the-it-tur...
FWIW, I think there's enough people in this audience that wouldn't be happy holding on to a job they aren't particularly interested in keeping up to date on, simply because they have the domain knowledge to make them "safe". I could be wrong though.