JEB
Legend
I mean, we can't say that deep lore did explicitly contribute to its success, either. It could have, but we don't know. (Would be an interesting poll, though.)The most popular setting in D&D is also it's most lore intensive setting by far, the Forgotten Realms, so to pretend the depth of it's lore had nothing to do with it's success is extremely disingenuous.
However, it does seem that the Realms having deep lore hasn't hurt the setting's longevity. It's been an actively supported setting since the 1980s, and folks still play in it, and it's outcompeted the game's original default setting (Greyhawk).