For one thing, the definitive source on the Zelda story is Eiji Aonuma, not Miyamoto, who gave us stuff like OoT->LoZ/Aol->LttP. Miyamoto is a game design genius, but he's really got no understanding of the overarching Zelda mythos. Aonuma is the guy who's actually dealing with continuity and the story.
For another thing, they've already told us that there is a timeline- subject to change as new games come out, but they do have their own timeline on file that they're working off of. For Miyamoto to give us a cop-out like "it's a legend" or "there is no timeline" would not only alienate a good chunk of the fanbase, but would also, well, *iss me off. They've worked on the timeline, we've worked on the timeline, and to drop the matter entirely would be one of the most boneheaded moves they could make.
So in conclusion, heck no.