I have worked with a number of people from my parents' generation that have had a job long enough to pull a pension and then have gotten another job.
now, I think once employees figured out they were expendable, the idea of looking for another job starting on day one of your present job has become the norm.
I believe the average job changes in a person's work span, say 20 to 64, is 7. some companies do not value "tree-huggers".
there has to be a happy medium. I've never been happy with a job I've had more than 4 years.