This is a joke, right?

I mean, I wouldn't mind clever in-jokey references to previous games in NPC dialogue or item descriptions, FFXI's writers have been being cute about those for years.

It's not -literally- the Golden Saucer, or the Crystal Tower, or whatever - just areas inspired by the areas from earlier games, thematically and aesthetically. Just like it's not -literally- the same Cid, for example, in every FF game. (It might be literally the same Gilgamesh, but that's venturing into fanwank territory.)

Eorzea isn't the Cleft of Dimensions, I'm afraid to say. It's its own game, with its own lore, and its own characters. The FF games are linked together by thematic elements, by imagery, by repeated motifs - if you want to play a fun, fanservicey crossover FF game, I've heard there's a nice PSP fighting game you may want to take a look at.