My thought is that it's hard to kill characters 'on accident' with plausible deniability that you're actually out to kill them.
Accidental downs and TPKs were a big thing loered in 4e and 5e. The monsters kill you, not the die.
And there is a reason for that; being a zero sucks. You either kept rolling toons to throw to the meatgrinder until one of them got enough levels to earn themselves a literal name (Elf 4 became Alara) or the DM played everything with kid gloves and pulled nearly every punch so that characters could actually be played. Those days when your wizard had a single spell slot, your thief's chance to successfully thieve was below 20%, and your fighter had single digit hp was fine when the game didn't care about things like backstory, motivation, or personality (which is why alignment worked fine as personality indicator then, "Chaotic Neutral" was a good indicator of what kind of shenanigans you'd be up to before you died).
Come Dragonlance and 2nd edition, the game was maturing to focus on characters and not just toons. Unfortunately, the rules didn't start catching up with it until the third edition. And there is nothing inherently wrong with the "roll up PCs fast and throw them at the dungeon until one of them sticks" method of play, but I think the market and player-base wanted something a little more refined and the game has moved towards that.
Exactly. There was aclear decision to make PCs tugher so PCs could play onto the stories the DM set up witout the DM playing with kids gloves or the PCs playing like chickens.
There was a clear decision that in 5e, you don't start at zero, hero, superhero,myth, or epic. You are year one Robin, Red Arrow, Wonder Girl. Day one TeenTitans or X men Team C. Superhero sidekicks.