NO NO NO
Stop making stuff up
I've raided since Onyxia was the top raid instance and the history of pug raiding is something like this:
Mar 2005 - Jan 2006 No one pugged raids. Very few people raided at all.
Feb 2006 - Jun 2006 semi pugs of MC and ZG started. Almost invariably people from more progressed guilds who had either left or didn't need their lockout would organise a raid by inviting as many people from notably successful raid guilds as possible adding a few hardcore pvpers (who were great raid dps) and rounding out with a few complete strangers.
Jul 2006-Dec 2006 widespread pugging of MC and ZG. Very little pugging of anything higher because those instances were considered too hard for people who didn't know what a rotation was and didn't know tactics (standard pug back then).
Jan 2007-May 2007 raids were the hardest ever. Karazhan was brutal. Attumen trash respawned every 15 minutes meaning if you were slow clearing it spawned on your casters and wiped you. Moroes extremely hard with the mortal striking add able to two shot a clothy and the garotte lasting 5 minutes. Even if you killed him garrotted people would bleed to death. No one pugged raids. Hell, no one even pugged heroics. The top guilds in the world were unable to finish TK- The Eye.
Jun 2007-Mar 2008 Karazhan successively nerfed to the point where people started to try pugs there. Usually depended on over-geared people with T5 or T6 loot leading. All higher content still too hard to pug.
Apr 2008 - Aug 2008 Kara pugs become common. Pugs becoming available for ZA and SSC but gear is carefully checked by the raid leader. Basically you have to have killed the content to get into the pug.
Sep 2008-Nov 2008. Sunwell Radiance removed. All raid bosses hit points lowered by 30%. Most content up to and including early SW25 is pugged. Kara through BT raids simply zerg down the bosses with a raid full of people not listening or knowing tactics, gameplay is more like Diablo 2 than traditional WOW raiding.
Dec 2008 to Feb 2008. Naxx is discovered and found to be easy. People still generally go with guilds though.
Mar 2008 to present. Widespread raid pugging usually with requests to Link Achievement.
Conclusion. Please do not spread the LIE that everyone pugged raids happily until achievements were introduced. Before achievements were introduced you would not be asked to link one because YOU WOULD NOT BE ASKED TO RAID.
(Reposted from the WoW EU R&D forums)