Death =/= Game Over
There are lots of ways to lose one's characters temporarily in older versions of D&D. Death is actually one of these and not necessarily the final curtain.
I'm not saying there is no way at all to lose a character permanently in D&D. It's simply the majority of so called game ending rolls were more Save Or Roll up a Temporary PC, not Save or Absolute Character Death (and never Save or Leave the Table - [Sorry Blackleaf]).
Dead characters can be resurrected, reincarnated, wished back to existence, heck, maybe even summoned and bound into another creature's body. "I'm playing two characters in one body!"
Temporary characters can retire when you get your old one back and be there in case it happens again. Becoming a thrall did not need to be the end either. However the time limit on getting Buddy back is probably a little shorter (yet less expensive) than death.
The catch is, there was a limit on how many times a character could lose everything (typically what we think of as death) and come back from it. This limited NPC villains too, so it wasn't all bad.
In the end, "The game can end for characters before retirement or natural death" should be in the rules the players read prior to play. Then give some basic overview of how such might happen. If the players are okay with it, game on.