How did your parents start with $0 but get "lucky" enough to work their way up some kind of occupational ladder to the point where they could live in a home and

How did your parents start with $0 but get "lucky" enough to work their way up some kind of occupational ladder to the point where they could live in a home and have 3 cars? Why aren't those same opportunities available for everybody in your opinion? They were available for your parents.