Woah.
"How big was the fish you caught in 3e?"
"OH MY! IT WAS THIS BIG! YOU SHOULD HAVE SEEN IT!"
Look, I get the impulse to tell war stories about older editions, and try to say, "You have it so good today! Back in my day, the game was so lethal that my character died before we even stated playing!!11!!!!"
But no ... 3e is certainly more lethal 5e (which does a LOT to make the game lower in lethality), but it was also deigned to be less lethal than the prior, TSR versions.
Quick reminder-
The primary and dispositive difference between 3e and the TSR versions was not ascending AC, or oodles of hit points, or saves based on abilities, or any of that nonsense ... it was the idea of the primacy of RAW.
The whole thing about the evolution from OD&D to AD&D (1e) to 2e is this- it was a game that allowed for many styles of play, but had rules that fundamentally were geared toward high-fatality possibilities and cautious exploration. However, post-Hickman, it gradually morphed into a game that was more about narrative and heroic fantasy. Because of the lack of the primacy of RAW, pumping out of supplements by TSR, and the common use of DM fiat, by the time of 2e (and certainly later-period 2e) it was easy to say that "AD&D" (and 2e) wasn't high in lethality. But that would be a table variation.
The actual play of TSR-era AD&D (without modification) was incredibly lethal- the hit points were much lower. The saves, while they increased across the board, could still be incredibly low (to use one example, in 1e a 15th level MU would need an 11 to save against poison or a breath weapon, and a 21st or higher level thief needed the same save v. breath weapon!). Poison was almost always lethal, and monsters and traps with poison were common. Low-level monsters often had abilities that would take characters out of combat (or out of life) permanently. Weird and deleterious aging effects were common. System shock rolls (or just being a soulless, dead-eyed elf) would keep you from being resurrected.
Again, a lot of tables didn't play with all rules, or softened them. But this was an issue of table variation and the choice of many table to go for a more heroic narrative style of play.
The overall story of D&D is a constant march toward less lethality over time. 3e is just a part of that trend.