Rugo is correct.
If you look at an old movie with a truck (like one of the last scenes in Hud, for example). You will see drivers getting in/out the passenger door (on street, or, by habit, at their homes).
Isn't much of a chore in a small old truck with a vinyl bench seat and flat floor. I'm imagining how much of a pain in the rear sliding over to the passenger side would be in my '13 Silverado.

I feel like people look at me funny for getting out of the passenger side when I'm out and about, but they're probably looking at me funny for being in a 67 year old truck.