Guilds are feeble now. With the loss of ML, they can’t really implement a system that ensures there are enough ppl on raid night. People don’t come to bosses they “don’t need loot from”.
In my last raiding guild in Wrath, which actually did the hard modes in ICC, we used a zero sum DKP system. If you were on your toon on raid night, even if you didn’t have a raid slot, but you were raid-ready if needed, you could park your raid toon right outside the instance and then do whatever you wanted on an alt, and you’d get DKP just like people in the raid. Why would I want DKP? Because that’s how you got loot, so when it was my turn in the raid I’d be able to get loot.
Why would I go back every time to kill bosses I didn’t need loot from? To help guildies, but also because I felt rewarded with DKP which helped me get the loot I wanted from other bosses.
That’s all gone.
Now on raid night we don’t ever fill up with guildies, and even when guildies are on they’re like “meh I don’t need anything from that boss so I’m not coming”. Because they know they can get in anytime they want and they’ll get what loot they need from personal loot.
So it’s not as easy as saying join a guild. Many guilds now can’t even fill a raid without grabbing a few pugs. The structure and systems that supported guilds have been gutted by blizzard, from the guild permissions to ML.
For those left in guilds, we spend most of our raid time trying to fill a mythic past mother, or even a heroic ghuun. Who wants to spend 1hr filling a freaking raid and then people can leave at any time because there’s no system to encourage working towards a common goal (like DKP).