It seems like you never played AD&D.
Admittedly not in a long time, but it was the first rpg I learned. And, I've been playing since 1982. Almost 36 years of gaming. A couple of decades of that with AD&D 1E and 2E.
I'd say that I've played it.
They were the most difficult to survive of all of the editions.
I'd agree to that. But what I said above still stands. Much of the challenge is in the hands of the DM, who should adjust the challenge appropriately for his group. The challenge should be different for three 1st level Thieves vs. a well rounded party of 8. If a group is all 1st level, or if a group averages 6th level, then the GM should balance the challenge to fit that group.
Same goes for low stats.
I ran an AD&D 2E game a few years ago where a player rolled up a female elf Warrior and rolled only 1 HP, with no CON bonus. The player played the hell out of that character, and she made second level. At that level, you know what she rolled? No kidding, 1 more HP, for a total of 2 HP. One hit would kill her.
The player continued to played the heck out of the character, finding other ways to shine instead of combat. She always avoided combat. She favored the bow. She started to become interested in magic, and we talked of going multi-class with her.
Then, she hit 3rd level. The player wanted to get her some hit points, so he decided to keep her as a Warrior for that level. The player rolled again. I'm not making this up. He roll 1 on the d10 a third time....
Incredible!
A 3rd level Warrior Elf, with exactly 3 HP!
We finished the adventure, then.
And, the player had a blast playing this character. She became a tactician. A thinker. And, always delivered damage from a distance.
The player, and the group, really got into this character. She only had 3 freakin' hit points, and it got to where the entire group of players was pulling for her.
It was a lot of fun.