I assume it's part of the general infantilization of society, the wimpier rulesets, and the storyfags rise to prominence. Everybody has their Half-dragon/Tiefling snowflake that is DESTINED to blah blah blah.
Players that are cool with PC death would DEFINITELY prefer their characters are each riding and blasting/hacking away at a separate one of Tiamat's heads as she plummets towards earth with broken wings while Planars and Solars sing in the chorus*, rather than run over by a drunk gnomes steam apparatus on the way home from the tavern, I totally get (and empathize) with those comments - depending on the ruleset you may have built in failsafes (Savage Worlds bennies, 5e Death saves, Resurrection spells).
Setting clear expectations is key.
I definitely make it clear up front to my players, that I'm not an adversarial DM, I do make clear that:
- Campaign areas are not necessarily level gated. This isn't an MMO. You see Troll sign at first level, you better bug out.
- Decisions have consequences.
Like
Tim Kask and the original crew my original group(s) coming up always had a few characters floating/active - everybody had a favorite, but we all had a rogue or magic-user tucked away, and a couple of good sports even had a cleric. Someone lost a character, they'd grab one of their backups, and the DM would
find a spot to work them in.
One of my favorite bits from Hackmaster 4th Edition (the first one... never mind) was the Protege rules, and since then I've tried to have some codified, measurable way to prep a backup character.
Since starting the 5e game, because we're mostly fulltime+ workers, I set it up with Adventuring guilds competing in the wildlands - so everyone has a reason to already know the replacement characters, and has some kind of connection built in.
For replacements, I'm using a simple version: Everyone has an alt, new ones start at the lowest level of the next tier from the highest characters: i.e. now that they're level 11, newbs come in at level 5.
*At least, that's how I hope the campaign ends!