An often-misconceived notion concerning Final Fantasy X and X-2 is that Shuyin is the basis of Tidus of Dream Zanarkand. Further, this belief has led some to believe that there is a temporal causality loop in place in Dream Zanarkand and that the place resets every so often. Both of these matters are inaccurate, however, and I will here explain why.
Note that the Fayth began dreaming 1000 years in Spira's past, basing Dream Zanarkand on Zanarkand as they had known it. Note also that time passes the same in Dream Zanarkand as it does in Spira. 10 years had passed in both Dream Zanarkand and Spira since Jecht's disappearance from Dream Zanarkand, his arrival in Spira, and his subsequent journey to Zanarkand with Braska and Auron:
(Said by Zanar, the Blitzball announcer from the opening events of the game in Dream Zanarkand.)
Quote:
"I was in a coffee shop, running away from home when I heard the news."
"Our hero, Jecht, gone, vanished into thin air!"
"My dad must have been his biggest fan. I knew how sad he'd be. Heck, we all were that day."
""Zanar," I says to myself, "What are you thinking?""
"I went running straight back home. We sat up talking 'bout Jecht all night."
"My dad and I never talked so much. Whoa... Didn't mean to reminisce, folks."
"Anyways... Ten years later, the Jecht Memorial Cup tournament is today!"
(After Tidus has gone to Spira and is in the Temple of Besaid.)
Quote:
::Tidus approaches a statue of a man clad in robes and holding a staff; one of the villagers approaches him::
"Ten years have passed since Lord Braska became high summoner."
"And finally we received a statue for our temple."
(Said by Wakka in Besaid.)
Quote:
Wakka
"Yuna came to this village ten years ago, when the last Calm started."
(On the S.S. Likki.)
Quote:
Tidus
"So, is Yuna's father famous or something?"
Wakka
"She's the daughter of High Summoner Braska! You saw his statue at the temple."
"Lord Braska defeated Sin ten years ago."
(On the S.S. Likki.)
Quote:
Tidus
"My old man, he died. Ten years ago, off the coast of Zanarkand."
Yuna
"I'm sorry."
Tidus
"He went out to sea for training one day...and never came back."
"And no one's seen him since then."
Yuna
"Why, that's the day that Jecht came to Spira."
"It's true! I first met Jecht ten years and three months ago!"
"I remember, that was the day my father left."
"The date fits, doesn't it?"
(On the S.S.Likki.)
Quote:
Yuna
"But, Sir Jecht was a kind and gentle man!"
Tidus
"Well, not my Jecht."
"Even ten years after he left..."
"just thinking about my old man got me angry. But maybe that was just my way of keeping him... Nah."
(On the S.S. Winno.)
Quote:
Yuna
"What would you do if you found him?"
Tidus
"Who knows? I thought he died ten years ago."
We also know that times passes the same there because Auron went to Dream Zanarkand to watch over Tidus when he was a child:
Quote:
Auron
"Jecht, Braska, and I... Together we defeated Sin, ten years ago."
"Then I went to Zanarkand...
"where I watched over you."
"So that one day I could bring you to Spira."
Quote:
Tidus
"Whenever my old man was around, my mother wouldn't even look at me."
"Maybe that's when I started to resent him, even hate him."
"When he left us..."
(Jecht vanishes, leaving no one beside Tidus' mother)
(Dream Zanarkand is shown, with Tidus as a child looking out at the sea)
Auron
"Is she all right?"
Tidus
"Why should you care?"
Auron
"If she dies, I wouldn't know what to do."
Tidus
"Don't say Mom is gonna die!"
Auron
"I apologize."
Bearing all this in mind, being that 1000 years have passed in Spira since Sin's arrival, it would also be 1000 years since the Fayth created Dream Zanarkand based on Zanarkand as they had known it. Dream Shuyin should have long since died, as there's no reason for the Fayth to have waited 1000 years to make someone based on him, nor is there any reason for the Fayth to be making people at this point any longer in the first place, as the people of Dream Zanarkand are living, breathing, reproducing people. The population of Dream Zanarkand would take care of the matter of providing future generations on their own. This is not to say, however, that Tidus couldn't possibly be a descendant of Dream Shuyin. It's not at all uncommon or unheard of for characters in Fantasy tales or RPGs to bear a striking resemblance to their ancestor (such as Marle in Chrono Trigger looking exactly like Queen Leene, her ancestor of five generations before).
Being aware of the matter of time passing the same in Dream Zanarkand as it does in Spira, some have come to believe that Dream Zanarkand must reset occasionally, as they see no other explanation for Tidus' resemblance to Shuyin other than Shuyin having been the basis for him. However, it's not at all accurate that Dream Zanarkand exists as a temporal causality loop that resets every few years. Most notably, this isn't suggested by the game, nor do we see evidence for it within the story. For that matter, there's not even any reason implied for such a thing to take place, or what purpose it could possibly serve.
That Zanarkand's technology had not advanced in 1000 years is often cited as evidence in this regard. However, civilzations reach peaks and do not advance until new resources become available or some catastrophe occurs. Dream Zanarkand was essentially its own world. Until Sin struck, there was no catastrophe, and there were no new resources to be discovered, obviously. For that matter, Yu Yevon's intention in regard to Dream Zanarkand was for it to keep the Zanarkand he had known alive forever, so it may well be that the possibility of technological advancement wasn't even present in Dream Zanarkand.
In any event, outside of the appearances of Tidus and Shuyin, no conceivable support for Dream Zanarkand resetting is present, and that's certainly not valid evidence on its own. On the part of the creators, Shuyin's appearance was intended for the purpose of causing Yuna to believe that Tidus may yet be alive and that she could find him. This caused her to join the Gullwings, and it provided a plot twist for the game when Shuyin was revealed to be someone who most obviously wasn't Tidus. Striking resemblances are no stranger to Fantasy tales, nor to Japanese tales in games or Anime (think of Taurus/Turlis and Gokou in Dragon Ball Z's third film,
The Tree of Might), nor to even Final Fantasy games (Maria and Celes in Final Fantasy VI, for instance), and quite often there is no relation or previous connection of any kind between the characters bearing resemblances to one another.
Most likely, I would conclude that the resemblances are just for the purposes of plot device: Giving Yuna a reason to join the Gullwings and providing a twist further into the game. At best, Tidus may be a descendant of Dream Shuyin if there, indeed, was one.
