I absolutely believed it. I was born in 1974 and lived my life counting those "70 or 80 years" from 1914 forward.
I wasn't supposed to graduate from high school, I wasn't supposed to get a job.
I'm 30, thankfully I left when I was 19-20 yoa and I have a life, a job, an education, and planning a retirement.... I quit actually believing it sometime around 1993 or 1994. It just didn't happen.