Probably died hundreds to thousands of times in MC. The easier runs later were possible because we were gearing up every week and then eventually had tier 2
That said, the type of player who plays WoW now has also changed since the original raiders entered Molten Core so many years ago. People still raid for fun, but like many things in modern society¹, you're also there to raid "efficiently."
This documentary that I watched recently called "Why it's rude to suck at World of Warcraft" is worth the watch. It talks about how raiding has changed from a fun thing that people used to do in vanilla WoW, where a guild of 40 people would put up with the weird gnome in the guild who wouldn't wear boots, to a hyper competitive pseudo-esport where players stopped tolerating that gnome player over a decade ago.
¹ trying not to sound too preachy, I personally love the "get good and keep improving yourself" aspect about WoW, and it's why I push in the game's rated arena brackets each season.
Molten Core was eventually easily clearable back then, so much so it was the hardest to get attendance for the <1 night it took. But I still think that had a lot more about being geared
Anyway, I didn't mean to suggest that all guilds used to have a weird bootless gnome-type raider back in vanilla. There were plenty of "hardcore" guilds around back then. What I meant was that there were a lot more of the bootless gnome-type players raiding back then, and they were tolerated by a lot more guilds and players in general because "that's just Jim, it's how he likes to play!"
As the documentary points out, the bootless gnome player has died out entirely outside of non-roleplay servers, because the playerbase as a whole decided that they want efficiency, speed and performance to be their #1 priority. That priority manifests itself everywhere in modern WoW.
Playing with modern Add-ons seems like the biggest difference. The gear requirements don't matter when you are playing with an aim-bot.
Also on the Add-on front. 20 years ago it felt like it was going down the path we see in tech where maximizing metrics become thing in themselves. I was a Druid healer and there was definitely pressure to spam for the readouts vs. the actual goal of making raid succeed and not letting the MT/OT whoever die.
As a non-US based player, back then we were still using modem and/or ISDN connections that would both drop quite frequently and had terrible latency.
WoW broke for me when cross-realm play was introduced. Prior to that, you gained a reputation on your server, so poor behavior was kept (somewhat) in check, and "randoms" you grouped with were therefore a) more willing to listen and follow alternative approaches, and b) worth teaching, because you knew you were likely to see them again. Complete anonymity removed the social contracts that made the game special.
I was just talking with my wife this morning about how different dungeons are now compared to back then, and how we'd be unlikely to wind up together if it were to happen today in modern WoW. She and I met while playing WoW back in Wrath; she played a paladin tank and was looking for a healer to heal a dungeon with her and her friends. I played a resto shaman at the time and decided to join them. We all ended up chatting so much that we added each other to our friend lists and started running dungeons together regularly. One thing lead to another and now we're happily married — 15 years later and still playing the game together.
I've been leveling some alts via dungeons recently, and the sense of community you get when you're in dungeons is completely gone. People do not talk to each other at all, there is zero communication. They are in and out of there as quickly as possible, no time for talking, no time for "hello."
The same is doubly true for LFR. 25 people in a raid and nobody talks to each other. If you're not at the boss by the time everyone else is, they're not waiting for you and they're going to pull. If you caused a wipe, you're going to get kicked from the group and replaced. They're just there to get loot for their alts and queue for the next wing of the raid.
There was one guy I'd group up with every Wednesday to run East Strat (this was early on, when it was a challenge for most PUGs) - he was a hunter (<Preyofwar>, if you're out there, it's been a long time, buddy) and I was a druid, so when we got a tank I healed, and when we got a healer I tanked; and, you know, hunters were intended to be group leaders, and mark + make the pulls - and for a while we made it a Thing; people would message us when they saw us come online.
This one time we grabbed a woman who mainly crafted - she'd sit outside the auction house handing out low-level bags to noobs - and had barely run dungeons before; it took some convincing to persuade her to come, and she didn't really know what she was doing (I think she was a resto shaman?). Halfway through, the assholes we'd picked up outside the instance started giving her grief in the chat - she'd wiped us at least a couple of times in a row - and she started apologizing and offering to go, and we said "no fucking way" and kicked them, and then called in favors with our guildmates to get some better-geared and more-experienced folks to help us carry her the rest of the way.
That's the sort of thing I loved about early WoW. We took the gamey side seriously - like, that guy and I really prided ourselves on how quickly we could run a group through the dungeon, and optimized the hell out of our pulls - but it was set up to remind you there was a human on the other side of the keyboard, too.
It's the best time I've had (or ever expect to have) with any video game, ever, and I'll never ever go back.
In one of my favorite fights the mages and I worked out a cool trick that I never saw in any strategy guide. Do you remember the banquet fight in Karazan? One of the bosses had pretty good spell resistance, and we suggested saving it for last. By that point in the fight I'd be helping the melee toons get it down, so my mana would be basically full at the end. The mages would totally stop casting on that boss, and aim to be at about half mana when combat stopped.
The instant we finished the mob off, the mages and I would run out the door, and I'd head up to the top of the stairs. With precise timing from a particular angle I could pull two groups of trash mobs in the next room, and make sure that they got to the stairs at the same time so they'd all get caught in my AoE. Between that spell, HoTs, and Thorns, druids could get phenomenal threat on grouped mobs. They'd hit me for a few seconds until they were sticky enough that the mages could AoE them down without getting touched. Then we'd sit down and drink/bandage, and laugh and point at the group if they'd taken too long looting.
Because no one particularly cared about their individual stats we saved everyone three or four minutes of waiting for those pulls. We were anything but an elite guild, on a bog-standard non-competitive server, but it was deeply satisfying to discover those small moments that contributed to everyone's success.
Guilds have enough resources and player skill to greatly limit the possiblity of unexpected chaos.
The servers came out in 2023.
I tend to agree though that for "content" reasons this sounds impossible, someone will wipe the raid just for the laughs.
At launch there was zero spell damage or healing on raid gear as a stat. You might find some green of shadow wrath but items like Robe of volatile power simply did not exist yet.
Warriors, the current top damage class, had a talent rework at BWL release which introduced their main damaging ability at nearly half the effectiveness of where it eventually end up.
Throw in world buff scheduling and the game is very different from how it played at launch.