That's a small amount of people. Most people in life move from job to job by choice as they gain skills or want to try something else.

Track all the people you run into in a week, and consider how many you think would choose to keep the job their in with the same employer for life. I don't know anyone I can think of who would choose that.

There's just too many opportunities, at all levels, to find better jobs over a 50 year span.