I don't follow your logic here. If there are only two things in the game, that we know of, that feature that crest, and both of them predate Link/Tetra, why does anything suggest the Royal Family is connected to that symbol?
The symbol was already an important part of the land before Link and Tetra arrived, and it adorns the vital building that makes the kingdom's train system possible. Additionally, the Spirit Pipes given to Tetra seem to suggest that the monarchy and the Lokomo are close. Finally, since the symbol has been seen on numerous vital things in the game, with the inverted triangle even showing up on the presumed sacred blade from the new ad, it is currently the best candidate for being the symbol of the new kingdom and land.
and Zelda's clothes still have the traditional Hylian Crest.
However, pretty much no attention has been given to that symbol so far, and people may not even recognize it as the Triforce at that time; remember, in TWW the people believed in the "Triumph Forks", and they apparently dismissed the idea of the Triforce as crazy.
I heard that beneath the big-head boulder on top of the hill here on Outset...
...is where the greatest treasures of all, the golden Triumph Forks, are buried.
But actually, fry, I must have misheard or something...
'Cause this one guy told me that what was actually buried beneath that weird rock was a chart to this shard of something called a Triforce.
Whoever heard of that? That's crazy! There's a big difference between "Triumph Forks" and "Triforce"! I mean, I think someone intentionally buried something misleading there.
Edited by Average Gamer, 25 November 2009 - 10:34 PM.