I feel I should point out I was introduced to the game by a high school friend and his father. His father's group had been playing for several years and stories of their campaigns don't sound like yours, either.As Mallus observed, by the second half of the '80s, one might never encounter anything but the kind of setup...
I wonder if a better indicator would be how a person came to D&D/RPG's: more from wargames or genre fiction?
My wargaming experience is limited to Risk and a few games of Axis and Allies (does chess count??). However, I've been reading SF/F for as long as I could read.
This assumes all like-level experiences are essentially the same. Have you ever read more than one book in the same genre? More than one Shakespeare comedy?One cannot really lose one's virginity more than once, and the tendency to recycle now-familiar elements and situations can lead to the game's becoming very stereotyped.