And presumably had enough cash that even being fired would not have caused major problems in your life, like an inability to pay rent/mortgage, eat, or afford health insurance.

Fair enough but you are pointing toward employment insecurity, low salary, and other stressful work conditions - these seem to be largely functions of job skills and industry, not how many years you spent at an employer. I would probably learn more about job insecurity working 2 years as an actor off Broadway than I would in 10 years as a programmer or product manager at Google or Facebook.