This is the RMT take btw
They do, people do MC every week despite the odds of getting items being extremely low.
Cata raids are too difficult for the majority of players in classic to do for fun. Its why people quit in OG cata.
People who did LFR in OG cata did it to see the raid, not for loot. Almost no one was full clearing cata raids at the time and it was a way for the playerbase to at least see the raids. Only the top 1% of players then did it for loot only