I was clearing out some of my inbox and I came across this great link in one those emails that you email yourself.
It is a stack of interviews of animators that have been in the industry for quite a few decades. I just listened to Randy Cartwright's interview because the name looked familiar and it turns out that his last name was familiar because his daughter (Mariel Cartwright) is the lead animator for the video game Skull Girls and Indivisible.
It is great to hear stories of the 9 Old Men and the fact that an animation career has always been like a career nowadays. There is no guarantee of lifelong employment under one company banner. It is all about making connections with fellow workers and doing good work and those two things are what lead to career longevity.