I don't think there's any evidence that this is true of Zelda. At the end of 2014, game footage was shown (which can't be said of Recore) and Aonuma publicly made his intention and even certainty clear that the game would be release in 2015. Something clearly changed in development, but at that point there's no reason to believe they didn't intend to release the game in 2015.
What changed was that the Wii U underperformed even Nintendo's lowest expectations, making it necessary to delay the game for a simultaneous release on NX.