I find this an extremely intriguing theory. I only recently found out about the Land of Ooo in Adventure Time taking place in a post-apocalyptic world and my mind was blown. This theory may serve to explain many things in the series, though not all of them.
There are certain things that are strictly magical. The spells given by the Great Fairies, the spells learned in AoL, and other various magical tools are just that, magic. No need to try and shove them into a preconceived notion of highly advanced technology.
Other things, not so much. I find it difficult to believe that various mechanical contraptions found in the games are anything but highly advanced technology left over from the old world. The hookshot being chief among them, nothing in their world would seem to suggest that the people living in the otherwise medieval worlds could construct such a device. The Dominion Rod is another one; while it is described as being magical, and by all rights it may very well be, the way in which it operates and the fact that it can lost its power seem to suggest a technological origin instead. Others include the Bombchus, the entirety of the Tower of the Gods, the Gust Bellows ad by extension the Gust Jar, and quite a bit of things that happen in SS. Similarly, the designs of many of the dungeons and other ancient buildings betray that highly advanced cultures well-versed in technology built them.
I had been suspecting for quite some time that many of the things that occur in the Zelda games have highly technological origins, and SS proved that to me. Their entire culture before Demise came and destroyed everything was very advanced. The series as a whole has a very strange development of technology. They start out highly advanced, become ruined as a result of Demise's actions, is rebuilt up as a result of Link and Zelda's colonization of the surface world, then splits off into three different timelines. The child timeline follows through on this advancement, and by the time TP rolls around they've gotten a lot closer to where they originally were. The adult timeline is hit by another apocalypse, then rebuilds to the point where trains are a common occurrence, placing them equivalently with the Industrial Revolution. The downfall timeline, however, faces a continual degrading of culture and technology until the world population is reduced to a scant few villages and randomly-populated caves. Very interesting indeed.
Furthermore, there are theories that state that the Triforce itself may be a sort of fusion between magic and technology. It has extremely magical powers, no doubt, but the way that it operates and chooses its master seems to suggest highly technological means as well. It could be that the magical powers are an attribute of the Triforce itself, or it may be that bringing the pieces together somehow activates a subroutine that contacts the goddesses in the distant nebula and allows the one who touches it to make their wish known to the goddesses, who then grant it.
