I agree with your sentiment in saying that Zelda should by no means become an annual franchise but should see a release schedule of every three years as opposed to every five.
I understand that Nintendo wants their Zelda titles to be of high quality, they seem to be too careful with this franchise. Each console generation should see something similar to the Nintendo 64 - two Zelda titles using the same engine. This would be far more efficient in releasing more Zelda titles within a consoles life cycle.
Perhaps this way they can release approximately two new Zelda titles and one remake per console.