Epic mounts were added to the trainers, both warlocks and paladins, in patch 3.0.3. During TBC it was required for both to complete the quest to get their epic mounts, in fact for blood elf paladins a new level 60 quest chain was created for that purpose with a new level 60 boss in Stratholme.
IIRC, it was the same for the Druid swift flight form, I have a memory of flying around in WotLK with it even though I never did the quest. As an aside, I think that they still kept all those quests in the game but with a different reward.
On the other side, you have this text : " Originally, the dreasteed mount required the completion of an epic quest chain. In [patch 2.4.0] the mount was added to class trainers; the quest chain remained available for those who still wanted to complete it until [patch 4.0.1], when it was removed entirely. "
I believe that is a mistake in the Wikia page because it also said
" **[Patch 3.0.3] Is now available on the trainer at level 61, requiring 150 riding skills, and the non-epic mount learned."
In the paladin mount quest pages is mentioned that the Epic mount was added to the trainer on patch 3.0.3 and the one is mentioned as added to the trainer on patch 2.4 is the 60% speed mount, but that one never required a quest chain and was added to the trainer with the purpose of making paladin and worlocks to not receive the 60% speed mount for free.