The Legend of Zelda: Tears of the Kingdom brought us more history and detail than we ever thought possible on the Zonai, but in the wake of this knowledge, a major part of Breath of the Wild was absent — Sheikah technology.
Now, in an interview with The Telegraph, Tears of the Kingdom's director Hidemaro Fujibayashi has offered some info on just what happened to the historical tech that helped Link take down Calamity Ganon. And it's not that deep at all — it all just "disappeared".
Depending on what you're expecting, Fujibayashi's answer might not be very satisfying, because it really is just a case of the Sheikah tech fulfilling its purpose. It's not explained in-game but Fujibayashi and the team at Nintendo had their own explanation for where it went and why it wasn't present in the sequel:
“[The Sheikah tech] disappeared after the Calamity was defeated (sealed). All of the people of Hyrule also witnessed this, but there is no one who knows the mechanism or reason why they disappeared, and it is considered a mystery. It is believed that since the Calamity disappeared, they also disappeared as their role had been fulfilled."
According to Fujibayashi, while people are aware of the Sheikah technology disappearing, no one knows the how part. But it's also not a huge deal, and the people acknowledge that its use is no longer needed as Calamity Ganon has been defeated.
It doesn't get any less vague with the rest of Fujibayashi's response, either. The director states that the citizens of Hyrule just haven't even bothered to look into it further, and have just accepted it as fact
"It is, anyway, commonplace for mysterious events and strange phenomena to occur in Hyrule. Thus, people have simply assumed the reason behind the disappearance to likely be related to ancient Sheikah technology and it seems there is no one who has tried to explore the matter further. The main civilizations in Breath of the Wild and Tears of the Kingdom are completely different, so we thought about the game based on concepts that match each of these civilizations.”
So, in short, it's all based on assumption, and we shouldn't worry about it — okay! Perhaps it has served its purpose and has decided it's no longer needed, of course, but we can't help but wish there was a bit more to it than that.
However, we weren't expecting a detailed explanation, so the team even acknowledging the question is probably all we're going to get. Anyway, does Link really even need Sheikah tech if he can build a car decked out in flamethrowers?