Because the developers designed the sync to item level sync players to i130, which is nearly double what your item level would have been back in the day when it was relevant. You’re able to push out more than enough damage to zerg a boss before they even start their more threatening mechanics. No one is going to take the time to kill Glasya’s Clockwork Wrights when they can just zerg him before the mechanic would even matter.

I’m completely in agreement with you, in that I wish the mechanics from when the 24-man alliance raids were relevant were still seen today (it’s sad to see what Weeping City has now become v.v — though it and Dun Scaith still wipe raids, as I found out when I was unlocking them on my alt yesterday), but it’s unlikely that any change will happen.