If your PC did fine it was because you cheated. Straight up. You fudged the dice.
You are making several assumptions here that may or may not be true...
I played 1e AD&D too long not fudging the dice to believe otherwise. And yes, I am well aware being asked for a saving throw is itself failure, but way to many 1e AD&D saving throws come down to by the numbers 50/50 save or die, and way too many get forced on you by non-passive NPCs etc to believe any of this. I know my players in the era were fudging, because their average rolls were probably around a 15. I have observed players never roll under a 10 for most of a year. I tolerated it because it wasn't worth fighting over, I didn't want to strain friendships and as long as the other players weren't complaining to me I wasn't being hurt.
Without fudging, I've had a dozen PCs I ran AD&D1e for make it to 10th from 1st, no rezzing needed... but it wasn't with published modules.
Several issues that may affect the lethality:
1st is that of comparable adventures. I tended to build dungeons that used more lower level foes. I seldom used save-or-die,
Second is that 15's are abnormal stats. For Method 0 (PHB), sure. But the DMG has 4 methods that are higher. Method I, you can expect one at 15. THe others, you can expect 2-3 15+ stats. They're not cheating, they're a DM's option for PC use. If you want to play legit paladins, use method IV
Third is comparable player playstyles. If your group is cautious enough, they seldom get in reach of death.
4th is that of how foes were run. I wasn't very good at it in the early 80's...
5th is the use or not of crits and fumbles - the core mechanic is just a nat 20 almost always hit. I don't know where you sat on that issue, but I didn't use crits in D&D until I got the Master Set...
I never had players fudging until senior year... because prior, all rolls were made in the open... save the few dictated otherwise in rules.