Talk about a misspelling that completely changes the context.
Yeah, there was a post on wowhead (I think it was?) breaking down the amount of hours per expansion. TBC will take you the longest no matter what because it is the least optimized for leveling. Back then quests were more spread out a lot of back and forth so that will translate into longer time. Newer expansions take less time as leveling has been more optimized over the years.