Quote Originally Posted by Yliette
I pray that you do not take this too offensively Masamune-1600 but Dream Zanarkand never was a location in the physical map of Spira. You might be referring the Zanarkand Ruins that's existent in the "real" Spira. But then again, Dream Zanarkand is just...what it says! A dream! That's the exact words of Bahamut's Fayth.

"This isn't a dream. That's because you ARE a dream. Your father, your mother, and the entire Zanarkand. They're all just dreams."

Well, they may not be the exact words of the Fayth but still they prove the exact point. He DID exist but only as a dream and not as a real person.

And it wasn't the summoning that linked Dream Zanarkand to Spira but the Fayth themselves. Since before the Eternal Calm, Sin reconquered on a decade basis hence the Fayth had to continue existing to give power to the Summoners. It was only when Sin has expired permanently that the Fayth may finally gain eternal rest and cease dreaming.

Since Zanarkand and its Summoners and Aeons lost the Machina War between Bevelle that took place a thousand years ago, the surviving citizens of Zanarkand transformed themselves into Fayths. And to somehow keep their Zanarkand alive, they gathered their memories and materialized them to create a whole new imaginary Zanarkand thus "Dream Zanarkand" came to be and Tidus and his family we're a fragment of that Dream Zanarkand.

"You know, we're pretty tired of dreaming. Do you mind if we rest?"

Although Tidus knew all along that Sin's permanent disappearance and Yuna's life would cost him his own existence, he still continued and sacrificed himself, not divulging to Yuna anything about his consequence. And now that Sin is gone for good, the Fayth may finally rest knowing that chaos and turmoil has finally been set aside. No longer do they have to dream about Zanarkand.

I'm afraid you have several notions confused. While it's commonly believed that Dream Zanarkand is an alternate dimension/another plane of existence, the fact remains that it is an actual physical location on Spira, merely far removed from physical locations the characters travel to in the game. This has been confirmed by the Final Fantasy X Ultimania Omega guide, which designates it as official SE canon.

In our case, the "Dreaming" and the "Summoning" are essentially synonymous. It would actually be fairly accurate to think of Dream Zanarkand and its citizens as Aeons. The memories of the Fayth were being summoned from within Sin, by Yu Yevon.

Fayth: The remaining summoners and the townspeople that survived the
war... They all became fayth-fayth for the summoning.

Tidus: The summoning... You mean Sin?

Fayth: No. I mean this place. A Zanarkand that never sleeps.

Tidus: What?

Fayth: The dreams of the fayth summoned the memories of the city. They
summoned all the buildings, all the people who lived there.

Tidus: The people... What, they're all dreams? Me, too?

Fayth: Yes, you're a dream of the fayth. You, your father, your mother,
everyone. All dreams. And if the fayth stop dreaming...
Obviously, when considered in correct context, it's clear that the term "dream" can be fairly misleading.

In any case, when the exertion of the Summoning ended, so did the "Dreaming." The force which physically bound Tidus to Spira was removed, and he died as a result.