Many years ago there was this thing called company loyalty. Often times people worked for the same company IN THE SAME JOB for years and years, usually until they collected a retirement pension and shot everyone the bird while saying "Siyonara, mo fos!" (I made that last part up.)
Today, this is unheard of. Acutally, many people still try to grasp for the role of up and coming pensioner in the U.S., but in the U.K. and in Canada, and I think pretty much anywhere else that has socialized medicine, employment is much more transitional. People are often on contract for a limited period, and after that's up they are left to the fates. Unemployment in the U.S. is a hugely feared condition, mostly because unemployment means no health care.
Not that I think that transitional or contract/short-term employment is a good thing, though I think more people in America would go that route in lieu of being in a stifling job if we had national healthcare.