As I stated before I feel that early editions revolved around the idea of characters roaming around“dungeons”, looting, killing and pretty much just trying to see how far they could push it before they died, either through bad choices, bad luck or some combination thereof. Pretty much it was a game of survival. Something I didn’t touch on last time was the idea that the rules state, quite specifically IIRC, that when you die you start over again at level 1. This to me is huge because it means that the classes are not just archetypes that define how you interact with the game world, but they were also intended to be a risk vs. reward mechanic.
The Rules Cyclopedia (which counts as an older edition of D&D) had explicit rules for introducing higher level player characters (which I recall as I quite liked them). So the explicit requirement to start over at first level isn't part of all older editions.